English

• 萘环是许多具有生物活性的天然产物的基本骨架, 其衍生物在材料科学与药学中也起着至关重要的作用(图 1)^[1-3].鉴于它们的重要性, 时至今日, 已经开发了多种合成取代的萘衍生物的方法^[4].值得注意的是, 在超分子化学和光化学领域中, 通过Suzuki-Miyaura偶联反应能够将高活性的萘硼酸或酯衍生物的萘环有效地引入到有使用价值的目标分子中^[5].传统的使用格氏试剂或有机锂试剂合成萘硼酸或酯衍生物的合成方法, 需要严格的无水环境、低温以及官能团耐受性较差等缺点^[6].虽然目前发展了使用过渡金属催化芳基卤化物或芳基的C—H键硼化^[7], 以及非过渡金属催化高官能团耐受性的芳基卤化物或芳基胺的硼化^[8]已经成为互补的合成方法, 但是, 这些合成方法通常需要预构芳环骨架.

  图 1

  

  图 1.  带有萘环的药物化学化合物

  Figure 1.  Naphthalene-containing pharmaceuticals

  下载: 全尺寸图片 幻灯片

  从合成的观点来看, 通过环化反应引入新的官能化基团是具有吸引力的.在这种情况下, 采用过渡金属催化或硼介导对单不饱和以及多不饱和底物进行环化硼化, 从而构建含硼取代基的碳环或者杂环化合物得到了广泛的关注^[9]. 2012年, Erker课题组^[10]采用了亲电性硼烷诱导的硼化环化策略, 以1, 2-双(炔基)苯衍生物为底物, RB(C₆F₅)₂作为硼源, 通过连续1, 1-碳硼化过程合成硼化的萘衍生物(图 2a). 2015年, Ingleson课题组^[11]以廉价的BCl₃作为硼源, 通过环化硼化-氧化两步实现了萘硼酸酯衍生物的合成(图 2b).基于我们课题组^[12-13]在2-(1-炔基)-2-烯烃-1-酮(共轭烯炔酮)化学转化的研究基础上, 我们设想是否能够通过BCl₃诱导实现其硼化环化, 进而为萘硼类化合物的合成提供新的途径.如果BCl₃活化共轭烯炔酮的炔烃部分, 使其碳中心具有足够的亲电性, 那么就可以通过分子内的SEAr反应直接得到萘硼类化合物.

  图 2

  

  图 2.  硼化环化反应生成含硼官能团的萘衍生物

  Figure 2.  Borylative cyclizations leading to boryl-functionalized naphthalene derivatives

  下载: 全尺寸图片 幻灯片

  2.   结果与讨论

  2.1   反应条件优化

  首先以共轭烯炔酮1a为模板底物, BCl₃为硼源, 二氯甲烷为溶剂, 在室温下反应8 h.随后加入频哪醇与N, N-二异丙基乙胺于室温下反应1 h.在此反应条件下以50%的产率得到了环化产物3a.接下来进一步考察了其他条件对反应的影响.首先尝试了以BBr₃、BF₃以及CatBCl为硼源, 仅能以极低的产率或无法得到目标产物(表 1, Entries 2~4).之后, 以BCl₃为硼源, 对BCl₃的用量以及不同的温度进行了筛选.结果表明, 在相对较低的反应温度通常比较高的反应温度反应效果更好(表 1, Entries 5~9).值得注意的是, 在-30 ℃下进行反应时, 通过将BCl₃的量稍微减少到1.8 equiv., 所需产物3a的产率可以显着提高到85%(表 1, Entry 10).增加或者减少BCl₃的量时, 将降低所需产物的收率(表 1, Entries 8, 11).最后, 筛选反应溶剂发现, 卤代烷烃通常比其他溶剂提供的结果更好, 二氯甲烷的效果最为显著(表 1, Entries 10~15), 并且, 使用四氢呋喃、1, 4-二氧六环、N, N-二甲基甲酰胺以及二甲基亚砜都无法得到目标产物(表 1, Entries 16~19).

  表 1

  

  表 1  反应条件优化^a

  Table 1.  Initial reaction discovery and condition optimization

  下载: 导出CSV

  Entry	[B] (equiv.)	Solvent	Temp/℃	Yieldb/%
  1	BCl3 (2.0)	DCM	r.t.	50
  2	BBr3 (2.0)	DCM	r.t.	6
  3	BF3•OEt2 (2.0)	DCM	r.t.	0
  4	CatBCl (2.0)	DCM	r.t.	0
  5	BCl3 (2.0)	DCM	50	42
  6	BCl3 (2.0)	DCM	0	54
  7	BCl3 (2.0)	DCM	－20	64
  8	BCl3 (2.0)	DCM	－30	75
  9	BCl3 (2.0)	DCM	－40	75
  10	BCl3 (1.8)	DCM	－30	(85) 80c
  11	BCl3 (1.5)	DCM	－30	54
  12	BCl3 (1.8)	DCE	－30	71
  13	BCl3 (1.8)	CHCl3	－30	65
  14	BCl3 (1.8)	CCl4	－30	20
  15	BCl3 (1.8)	Toluene	－30	14
  16	BCl3 (1.8)	THF	－30	NR
  17	BCl3 (1.8)	1,4-Dioxane	－30	NR
  18	BCl3 (1.8)	DMF	－30	NR
  19	BCl3 (1.8)	DMSO	－30	NR
  a Reaction conditions: 1a (0.2 mmol), BCl3 (1.0 mol•L-1 in DCM), in solvent (2.0 mL), 8.0 h, under Ar. CatBCl=B-chlorocatecholborane. DIPEA=N, N-Diisopropylethylamine. NR=no reaction. b Determined by 1H NMR analysis using dibromomethane as an internal standard. c Isolated yield.

  2.2   底物普适性研究

  通过对反应条件的系统优化, 最终确定了反应的最优条件: BCl₃ (1.8 equiv.)为硼源, 二氯甲烷为溶剂, 反应温度为-30 ℃.在此条件下对底物的范围进行了考察(图 3).结果表明, (1)这种环合方法难以耐受在叁键位置(R¹)上烷基的存在, 带有烷基的炔烃生成了非常复杂的混合物, 并且很难干净地分离出所需的萘硼酸酯. (2)连接至双键(R³)的带有不同取代基的芳基对反应的产率有很大影响.例如, 在苯基上没有甲氧基的1b, 反应仅得到中等程度的分离收率(67%), 并且通过X射线分析进一步证实产物3b的结构^[14].然而, 具有强供电子取代基的底物收率相对较低, 例如, 与双键相连的苯环上带有甲硫基的1c、苯基的1d与三甲氧基的1e反应, 分别可得到12%, 37%和54%分离产率.含醚底物得到相对较低的产率可能归因于BCl₃裂解了醚键^[11]. (3)炔基上具有不同的芳烃对反应的影响较小, 以50%~90%的分离产率得到了相应的萘硼酸酯衍生物3f~3j.同时, 将3i进行克级规模制备, 可以得到79% (1.71 g)的分离产率.此外, 炔基上有杂芳烃取代基时, 例如2-噻吩, 同样能够表现出良好的反应性(3k, 54%). (4)该反应过程对羰基上的取代基R²表现出良好的耐受性3l~3p.

  图 3

  

  图 3.  底物扩展

  Figure 3.  Scope of 2-(1-alkynyl)-2-alken-1-ones

  下载: 全尺寸图片 幻灯片

  有趣的是, 当连接在双键上的苯环间位为甲氧基的共轭烯炔酮1q在标准反应条件下反应时, 在甲氧基的邻位发生区域特异性环化, 可以获得相应的萘硼酸酯化合物3q, 并且将BCl₃的用量增加至4.0 equiv., 能够将产率提高至72% [Eq. (1)].然而, 当使用连接在双键上的苯环邻位为甲氧基的共轭烯炔酮1r时, 未观察到环化产物萘硼酸酯化合物3r [Eq. (2)].同时, 没有酮羰基的简单共轭烯炔1s^[15]在BCl₃作用下, 并没有得到环化目标产物[Eq. (3)].尽管酮羰基的作用目前尚不清楚, 推测其可能扮演着导向基团的作用^[16], 酮羰基与BCl₃相互作用利于其对炔基的活化.

  2.3   产物转化的研究

  通过使用在双键和叁键位置的苯环上带有两个甲氧基的共轭烯炔酮1i, 可以实现克级规模合成高度官能化的萘硼酸酯化合物.其中存在的硼酸酯为衍生化提供了许多可能(图 4).例如, 在化学计量的CuBr₂的作用下, 3i的硼酸酯基很容易转化成溴, 以61%的产率得到溴萘化合物4a; 3i通过经典的Suzuki-Miyaura偶联反应与2-溴萘作用, 以59%的产率得到联萘化合物4b; 叠氮基可以轻松地通过3i与TMSN₃在铜催化下引入到萘环上, 叠氮化萘4c以67%产率获得; 通过用KOMe处理3i, 硼酯基容易被除去, 并且氢化萘4d以61%的产率获得.

  图 4

  

  图 4.  3i的产物转化

  Figure 4.  Synthetic transformation of 3i

  下载: 全尺寸图片 幻灯片

  (1)

  (2)

  (3)

  3.   结论

  我们研究了无金属的BCl₃介导的2-(1-炔基)-2-烯烃-1-酮的硼化环化反应, 能够实现一步合成有价值的多官能化萘硼酸酯化合物.该策略为构建各种萘硼化合物提供了一种简洁的方法.目前正在进行进一步研究, 包括对BCl₃介导的环化过程的机理和合成应用, 以及酮羰基在其中的作用机制.

  4.   实验部分

  4.1   仪器与试剂

  2-(1-炔基)-2-烯烃-1-酮根据相应的参考文献合成得到^[17], 其余试剂均从商业渠道上购买得到(Energy, 国药, TCI and J & K), 未经纯化直接使用. ¹H NMR及¹³C NMR在Bruker (400 MHz), Bruker (500 MHz)测得.样品溶于氘代氯仿于常温下测试, TMS为内标.使用NMR标准如下: CDCl₃ δ 7.26 (¹H NMR), 77.2 (¹³C NMR).

  4.2   化合物3a~3q的合成

  在带有搅拌子干燥的10 mL Schlenk管中加入1 (0.2 mmol)和2.0 mL二氯甲烷, 冷却至-30 ℃.往其中加入BCl₃ (0.36 mmol, 1 mol•L^-1 in DCM), 搅拌约8 h, 通过薄层色谱(TLC)检测1消失.随后加入频哪醇(0.6 mmol)和N, N-二异丙基乙胺(3 mmol), 于室温下搅拌1 h.最后, 经柱色谱分离得到相应的产物, 洗脱剂V(石油醚):V(乙酸乙酯)=6:1.

  1-(6-甲氧基-4-苯基-3-硼酸酯基萘-2-基)乙-1-酮(3a):红色固体, 产率80%. m.p. 148~150 ℃; ¹H NMR (500 MHz, Chloroform-d) δ: 9.26 (d, J=11.3 Hz, 1H), 8.19 (d, J=11.1 Hz, 1H), 7.55~7.47 (m, 2H), 7.43 (t, J=7.6 Hz, 2H), 7.40~7.33 (m, 1H), 7.07 (dd, J=11.3, 2.8 Hz, 1H), 6.92 (dd, J=11.1, 2.8 Hz, 1H), 3.96 (s, 3H), 2.80 (s, 3H), 1.22 (s, 12H); ¹³C NMR (126 MHz, CDCl₃) δ: 195.37, 168.74, 137.82, 137.64, 137.32, 137.09, 136.98, 135.66, 131.07, 130.73, 127.94, 126.96, 114.49, 114.21, 83.99, 56.14, 30.83, 25.01. HRMS (ESI) calcd for C₂₅H₂₇BNaO₄ [M+Na]⁺ 425.1899, found 425.1907.

  1-(4-苯基-3-硼酸酯基萘-2-基)乙-1-酮(3b):白色固体, 产率67%. m.p. 176~178 ℃; ¹H NMR (500 MHz, Chloroform-d) δ: 8.44 (s, 1H), 7.99 (d, J=8.1 Hz, 1H), 7.58~7.53 (m, 1H), 7.53~7.38 (m, 7H), 2.79 (s, 3H), 1.10 (s, 12H); ¹³C NMR (126 MHz, CDCl₃) δ: 199.60, 145.30, 139.51, 137.07, 134.83, 132.59, 131.00, 130.06, 129.41, 128.58, 127.72, 127.50, 126.65, 126.60, 83.39, 25.27, 25.09. HRMS (ESI) calcd for C₂₄H₂₅BNaO₃ [M+Na]⁺ 395.1793, found 395.1799.

  1-(6-甲硫基-4-苯基-3-硼酸酯基萘-2-基)乙-1-酮(3c):紫色固体, 产率12%. m.p. 106~108 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.02 (d, J=10.8 Hz, 1H), 8.03 (d, J=10.6 Hz, 1H), 7.49 (d, J=7.0 Hz, 2H), 7.43 (t, J=7.4 Hz, 2H), 7.37 (d, J=7.1 Hz, 1H), 7.21 (dd, J=10.8, 1.8 Hz, 1H), 7.06 (dd, J=10.6, 1.8 Hz, 1H), 2.80 (s, 3H), 2.53 (s, 3H), 1.23 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 195.06, 156.31, 139.08, 137.87, 136.89, 136.77, 135.17, 135.04, 131.05, 131.01, 128.02, 127.10, 123.31, 122.81, 84.05, 30.82, 25.03, 16.19. HRMS (ESI) calcd for C₂₅H₂₇BNaO₃S [M+Na]⁺ 441.1671, found 441.1673.

  1-(4, 6-二苯基-3-硼酸酯基萘-2-基)乙-1-酮(3d):黄色固体, 产率37%. m.p. 237~238 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 8.42 (s, 1H), 8.02 (d, J=8.5 Hz, 1H), 7.78 (dd, J=8.5, 1.8 Hz, 1H), 7.66 (d, J=1.7 Hz, 1H), 7.53~7.49 (m, 2H), 7.48~7.34 (m, 6H), 7.36~7.27 (m, 1H), 2.76 (s, 3H), 1.09 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 199.49, 145.56, 141.26, 140.74, 139.41, 137.09, 135.14, 131.78, 131.03, 129.99, 129.78, 128.86, 127.82, 127.69, 127.61, 127.48, 126.38, 124.49, 83.42, 25.28, 25.14. HRMS (ESI) calcd for C₃₀H₂₉BNaO₃ [M+Na]⁺ 471.2107, found 471.2110.

  1-(5, 6, 7-三甲氧基-4-苯基-3-硼酸酯基萘-2-基)乙-1-酮(3e):黄色固体, 产率54%. m.p. 173~175 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 8.25 (s, 1H), 7.38~7.27 (m, 5H), 7.10 (s, 1H), 3.99 (s, 3H), 3.86 (s, 3H), 3.19 (s, 3H), 2.70 (s, 3H), 1.06 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 199.23, 153.39, 150.04, 144.61, 143.16, 142.95, 136.55, 130.94, 129.78, 129.15, 126.54, 126.21, 125.41, 104.37, 83.26, 60.87 (d, J=2.5 Hz), 60.59, 55.79 (d, J=2.6 Hz), 25.37. HRMS (ESI) calcd for C₂₇H₃₁BNaO₆ [M+Na]⁺ 485.2111, found 485.2111.

  1-(4-对氟苯基-3-硼酸酯基萘-2-基)乙-1-酮(3f):白色固体, 产率70%. m.p. 206~208 ℃; ¹H NMR (500 MHz, Chloroform-d) δ: 8.45 (s, 1H), 8.00 (dd, J=8.1, 1.3 Hz, 1H), 7.60~7.53 (m, 1H), 7.54~7.47 (m, 1H), 7.45 (dd, J=8.4, 1.2 Hz, 1H), 7.42~7.35 (m, 2H), 7.22~7.14 (m, 2H), 2.78 (s, 3H), 1.14 (s, 12H); ¹³C NMR (126 MHz, CDCl₃) δ: 199.57, 162.58 (d, J=246.2 Hz), 144.08, 137.08, 135.43 (d, J=3.3 Hz), 134.88, 132.67 (d, J=8.0 Hz), 132.61, 130.25, 129.52, 128.76, 126.77, 126.31, 114.64 (d, J=21.2 Hz), 83.47, 25.23, 25.12. HRMS (ESI) calcd for C₂₄H₂₄BFNaO₃ [M+Na]⁺ 413.1699, found 413.1701.

  1-(4-对甲基苯基-3-硼酸酯基萘-2-基)乙-1-酮(3g):白色固体, 产率58%. m.p. 172~174 ℃; ¹H NMR (500 MHz, Chloroform-d) δ: 8.43 (s, 1H), 7.98 (d, J=8.0 Hz, 1H), 7.58~7.50 (m, 2H), 7.51~7.44 (m, 1H), 7.30 (q, 4H), 2.78 (s, 3H), 2.47 (s, 3H), 1.11 (s, 12H); ¹³C NMR (126 MHz, CDCl₃) δ: 199.61, 145.41, 137.11, 137.08, 136.49, 134.99, 132.60, 130.87, 129.95, 129.38, 128.49, 128.31, 126.66, 126.60, 83.37, 77.30, 77.04, 76.79, 25.28, 25.06, 21.28. HRMS (ESI) calcd for C₂₅H₂₇BNaO₃ [M+Na]⁺ 409.1950, found 409.1951.

  1-(6-甲氧基-4-对溴苯基-3-硼酸酯基萘-2-基)乙-1-酮(3h):红色固体, 产率50%. m.p. 121~123 ℃; ¹H NMR (500 MHz, Chloroform-d) δ: 9.21 (d, J=11.3 Hz, 1H), 8.12 (d, J=11.0 Hz, 1H), 7.60~7.56 (m, 2H), 7.42~7.36 (m, 2H), 7.07 (dd, J=11.3, 2.8 Hz, 1H), 6.92 (dd, J=11.1, 2.8 Hz, 1H), 3.96 (s, 3H), 2.81 (s, 3H), 1.27 (s, 12H); ¹³C NMR (126 MHz, CDCl₃) δ: 195.23, 168.90, 137.45, 137.26, 136.71, 136.09, 136.08, 135.55, 132.68, 131.09, 131.06, 121.13, 114.78, 114.30, 84.07, 56.20, 30.81, 25.06. HRMS (ESI) calcd for C₂₅H₂₆BBrNaO₄ [M+Na]⁺ 503.1004, found 503.1005.

  1-(6-甲氧基-4-对甲氧基苯基-3-硼酸酯基萘-2-基)乙-1-酮(3i):红色固体, 产率90%. m.p. 150~151 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.21 (d, J=11.3 Hz, 1H), 8.15 (d, J=11.1 Hz, 1H), 7.42 (d, J=8.5 Hz, 2H), 7.03 (dd, J=11.3, 2.8 Hz, 1H), 6.98 (d, J=8.6 Hz, 2H), 6.89 (dd, J=11.1, 2.8 Hz, 1H), 3.94 (s, 3H), 3.87 (s, 3H), 2.80 (s, 3H), 1.24 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 195.27, 168.65, 158.81, 137.83, 137.46, 137.10, 136.91, 135.55, 132.09, 130.65, 129.42, 114.34, 114.02, 113.40, 83.94, 56.11 (d, J=3.1 Hz), 55.39 (d, J=2.7 Hz), 30.81 (d, J=1.9 Hz), 25.05. HRMS (ESI) calcd for C₂₆H₂₉B- NaO₅ [M+Na]⁺ 455.2005, found 455.2011.

  1-(7-甲氧基-2-硼酸酯基-[1, 1']-联萘]-3-基)乙-1-酮(3j):黄色固体, 产率70%. m.p. 178~179 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 8.42 (s, 1H), 7.98~7.84 (m, 3H), 7.57 (t, J=7.6 Hz, 1H), 7.49 (dd, J=7.0, 1.3 Hz, 1H), 7.47~7.38 (m, 1H), 7.35~7.21 (m, 2H), 7.16 (dd, J=8.9, 2.5 Hz, 1H), 6.47 (d, J=2.4 Hz, 1H), 3.44 (s, 3H), 2.75 (s, 3H), 0.91 (s, 6H), 0.64 (s, 6H); ¹³C NMR (101 MHz, CDCl₃) δ: 199.29, 159.90, 141.97, 137.12, 136.99, 135.54, 133.43, 133.18, 131.12, 130.09, 129.01, 128.09, 127.89, 127.61, 127.05, 125.93, 125.72, 125.13, 119.10, 105.54, 83.02, 55.06, 25.12 (d, J=1.9 Hz), 24.71 (d, J=9.7 Hz). HRMS (ESI) calcd for C₂₉H₂₉BNaO₄ [M+Na]⁺ 475.2056, found 475.2057.

  1-(6-甲氧基-4-噻吩-3-硼酸酯基萘-2-基)乙-1-酮(3k):红色固体, 产率54%. m.p. 133~134 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.26 (d, J=11.3 Hz, 1H), 8.38 (d, J=11.1 Hz, 1H), 7.40 (dd, J=5.1, 1.3 Hz, 1H), 7.23~7.03 (m, 3H), 6.96 (dd, J=11.1, 2.8 Hz, 1H), 3.95 (s, 3H), 2.79 (s, 3H), 1.28 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 195.32, 169.02, 138.70, 137.75, 137.61, 137.11, 135.91, 130.54, 128.97, 128.37, 126.97, 125.85, 115.14, 114.55, 84.16, 56.21, 30.84, 25.06. HRMS (ESI) calcd for C₂₃H₂₅BNaO₄S [M+Na]⁺ 431.1463, found 431.1473.

  (6-甲氧基-4-对甲氧基苯基-3-硼酸酯基萘-2-基)(噻吩-2-基)甲酮(3l):红色固体, 产率76%. m.p. 73~74 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 8.80 (d, J=11.1 Hz, 1H), 8.21 (d, J=11.0 Hz, 1H), 7.63 (dd, J=4.9, 1.2 Hz, 1H), 7.49 (dd, J=3.8, 1.2 Hz, 1H), 7.43 (d, J=8.6 Hz, 2H), 7.08~7.05 (m, 1H), 6.98 (d, J=8.6 Hz, 2H), 6.92~6.82 (m, 2H), 3.92 (s, 3H), 3.87 (s, 3H), 0.97 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 186.14, 169.30, 158.67, 148.23, 137.67, 137.64, 136.16, 135.98, 135.00, 132.81, 132.27, 131.82, 129.38, 127.54, 113.28, 113.21, 113.15, 83.86, 56.16, 55.40, 24.63. HRMS (ESI) calcd for C₂₉H₃₀BO₅S [M+Na]⁺ 501.1907, found 501.1906.

  环丙基(6-甲氧基-4-对甲氧基苯基-3-硼酸酯基萘-2-基)甲酮(3m):红色固体, 产率71%. m.p. 101~102 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.22 (d, J=11.2 Hz, 1H), 8.16 (d, J=11.0 Hz, 1H), 7.44 (d, J=8.6 Hz, 2H), 7.01~6.94 (m, 3H), 6.85 (dd, J=11.1, 2.7 Hz, 1H), 3.92 (s, 3H), 3.87 (s, 3H), 2.74~2.67 (m, 1H), 1.39~1.34 (m, 2H), 1.22 (s, 12H), 1.05~0.98 (m, 2H); ¹³C NMR (101 MHz, CDCl₃) δ: 198.34, 168.68, 158.72, 137.42, 137.35, 136.98, 136.94, 135.16, 132.36, 132.09, 129.60, 113.76, 113.38, 83.95, 56.09, 55.40, 25.01, 21.45, 11.42. HRMS (ESI) calcd for C₂₈H₃₂BO₅ [M+Na]⁺ 459.2342, found 459.2340.

  环己基(6-甲氧基-4-对甲氧基苯基-3-硼酸酯基萘-2-基)甲酮(3n):红色固体, 产率67%. m.p. 127~128 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.01 (d, J=11.3 Hz, 1H), 8.12 (d, J=11.0 Hz, 1H), 7.43~7.38 (m, 2H), 7.01~6.92 (m, 3H), 6.83 (dd, J=11.1, 2.8 Hz, 1H), 3.92 (s, 3H), 3.86 (s, 3H), 3.31~3.20 (m, 1H), 2.10~1.26 (m, 12H), 1.24 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 203.28, 168.70, 158.72, 137.60, 137.40, 137.13, 136.91, 135.38, 132.23, 131.34, 129.58, 113.66, 113.26, 83.91, 56.08, 55.39, 49.70, 29.56, 26.06, 25.93, 25.17. HRMS (ESI) calcd for C₃₁H₃₈BO₅ [M+Na]⁺ 501.2812, found 501.2818.

  1-(6-甲氧基-4-对甲氧基苯基-3-硼酸酯基萘-2-基)戊-1-酮(3o):红色固体, 产率91%. m.p. 180~181 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.29 (d, J=11.3 Hz, 1H), 8.14 (d, J=11.1 Hz, 1H), 7.46~7.38 (m, 2H), 7.08~6.94 (m, 3H), 6.88 (dd, J=11.1, 2.8 Hz, 1H), 3.94 (s, 3H), 3.87 (s, 3H), 3.14 (t, 2H), 1.85~1.77 (m, 2H), 1.53~1.40 (m, 2H), 1.23 (s, 12H), 0.97 (t, J=7.3 Hz, 3H); ¹³C NMR (101 MHz, CDCl₃) δ: 198.49, 168.65, 158.78, 137.66, 137.51, 137.45, 136.82, 135.42, 132.17, 130.52, 129.54, 114.12, 113.79, 113.34, 83.96, 56.09 (d, J=2.3 Hz), 55.39 (d, J=2.1 Hz), 42.28, 26.98, 25.08, 22.69, 14.22. HRMS (ESI) calcd for C₂₉H₃₅BNaO₅ [M+Na]⁺ 497.2475, found 497.2477.

  苯基(4-苯基-3-硼酸酯基萘-2-基)甲酮(3p):白色固体, 产率58%. m.p. 147~148 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 8.19 (s, 1H), 7.91~7.82 (m, 3H), 7.66~7.56 (m, 1H), 7.57~7.40 (m, 10H), 1.08 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 197.63, 145.81, 139.70, 137.91, 136.76, 134.47, 132.81, 132.13, 131.92, 131.00, 129.86, 129.53, 128.58, 128.35, 127.79, 127.56, 126.73, 126.57, 83.66, 25.03. HRMS (ESI) calcd for C₃₀H₂₉BNaO₃ [M+Na]⁺ 457.1951, found 457.1948.

  1-(5-甲氧基-4-对甲氧基苯基-3-硼酸酯基萘-2-基)乙-1-酮(3q):黄色固体, 产率72%. m.p. 179~180 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 8.33 (s, 1H), 7.53 (d, J=8.1 Hz, 1H), 7.41 (t, J=7.9 Hz, 1H), 7.21 (d, J=8.4 Hz, 2H), 6.87 (d, J=8.3 Hz, 2H), 6.82 (d, J=7.7 Hz, 1H), 3.85 (s, 3H), 3.38 (s, 3H), 2.72 (s, 3H), 1.09 (s, 12H); ¹³C NMR (101 MHz, CDCl₃) δ: 199.49, 158.27, 157.05, 143.63, 136.92, 136.57, 134.91, 130.69, 130.13, 127.04, 126.36, 122.35, 111.84, 109.23, 83.33, 77.44, 77.12, 76.80, 55.75, 55.53, 25.47, 25.37. HRMS (ESI) calcd for C₂₆H₂₉BNaO₅ [M+Na]⁺ 455.2005, found 455.1995.

  4.3   化合物4a~4d的合成

  在带有搅拌子的10 mL Schlenk管中加入3i (0.2 mmol)、溴化铜(0.6 mmol)、2.0 mL甲醇以及2 mL水, 加热回流约6 h.通过薄层色谱(TLC)检测3i消失.加入乙醚萃取, 有机相用饱和食盐水洗, 无水硫酸钠干燥, 旋干溶剂, 经柱色谱分离得到相应的产物, 洗脱剂V(石油醚):V(乙酸乙酯)=2:1, 得1-(3-溴-6-甲氧基-4-对甲氧基苯基萘-2-基)乙-1-酮(4a)^[18]:红色固体, 产率61%. m.p. 133~134 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.41 (d, J=11.3 Hz, 1H), 8.10 (d, J=11.2 Hz, 1H), 7.35 (d, J=8.1 Hz, 2H), 7.13~7.03 (m, 3H), 6.96 (dd, J=11.3, 2.8 Hz, 1H), 3.97 (s, 3H), 3.90 (s, 3H), 2.89 (s, 3H); ¹³C NMR (101 MHz, CDCl₃) δ: 197.15, 168.85, 159.13, 137.96, 136.29, 135.12, 135.06, 132.39, 131.77, 127.09, 124.87, 124.31, 116.04, 114.77, 113.80, 56.23, 55.32, 32.47. HRMS (ESI) calcd for C₂₀H₁₇BrNaO₃ [M+Na]⁺ 407.0253, found 407.0254.

  在带有搅拌子的20 mL Schlenk管中加入3i (0.2 mmol)、2-溴萘(0.24 mmol)、碳酸钾(1 mmol)和四三苯基膦钯(0.02 mmol, 10 mol%), 随后添加4.5 mL N, N-二甲基甲酰胺以及0.5 mL水, 加热至80 ℃, 反应8 h.反应结束, 加入20 mL水淬灭, 加入氯仿萃取, 有机相用饱和食盐水洗, 无水硫酸钠干燥, 旋干溶剂, 经柱色谱分离得到相应的产物, 洗脱剂V(石油醚):V(乙酸乙酯)=2:1, 得1-(7-甲氧基-1-对甲氧基苯基-[2, 2'-联萘]-3-基)乙-1-酮(4b)^[19]:红色固体, 产率59%. m.p. 287~288 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.29 (d, J=11.2 Hz, 1H), 8.24 (d, J=11.2 Hz, 1H), 7.85~7.69 (m, 4H), 7.51~7.42 (m, 2H), 7.34 (d, J=8.4 Hz, 1H), 7.10 (d, J=8.0 Hz, 3H), 6.97 (dd, J=11.2, 2.7 Hz, 1H), 6.80 (d, J=8.3 Hz, 2H), 3.97 (s, 3H), 3.76 (s, 3H), 2.03 (s, 3H); ¹³C NMR (101 MHz, CDCl₃) δ: 199.65, 168.64, 158.30, 146.51, 137.99, 136.69, 135.47, 135.40, 135.09, 133.11, 132.39, 132.27, 131.23, 130.61, 130.00, 128.53, 128.14, 127.72, 127.49, 126.95, 126.19, 126.12, 115.09, 113.98, 113.64, 56.15, 55.16, 32.00. HRMS (ESI) calcd for C₃₀H₂₄NaO₃ [M+ Na]⁺ 455.1618, found 455.1615.

  往2 mL甲醇溶液加入3i (0.2 mmol)、四丁基氟化铵(0.24 mmol)、叠氮基三甲基硅烷(0.24 mmol)以及氯化亚铜(0.02 mmol, 10 mol%), 加热回流至原料消失, 经柱色谱分离得到相应的产物, 洗脱剂V(石油醚):V(乙酸乙酯)=6:1, 得1-(3-叠氮基-6-甲氧基-4-对甲氧基苯基萘-2-基)乙-1-酮(4c)^[20]:橘黄色固体, 产率67%. m.p. 158~159 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 8.18 (d, J=10.7 Hz, 1H), 7.73 (d, J=11.7 Hz, 1H), 7.35 (d, J=8.2 Hz, 2H), 7.05 (d, J=8.2 Hz, 2H), 6.89 (dd, J=11.8, 2.8 Hz, 1H), 6.78 (dd, J=10.8, 2.9 Hz, 1H), 3.87 (s, 6H), 2.80 (s, 3H); ¹³C NMR (101 MHz, CDCl₃) δ: 194.27, 161.96, 158.96, 157.74, 138.10, 137.20, 131.20, 128.64, 126.10, 125.60, 120.87, 118.76, 114.74, 109.86, 108.76, 55.80, 55.37, 31.79. HRMS (ESI) calcd for C₂₀H₁₉NNaO₃ [M+2H+Na-2N]⁺ 344.1262, found 344.1261.

  往2 mL甲醇溶液加入3i (0.2 mmol)以及甲醇钾(0.01 mmol, 5 mol%), 加热至120 ℃反应12 h至原料消失, 经柱色谱分离得到相应的产物, 洗脱剂V(石油醚):V(乙酸乙酯)=4:1, 得1-(6-甲氧基-4-对甲氧基苯基-2-基)乙-1-酮(4d)^[21]:红色固体, 产率61%. m.p. 180~181 ℃; ¹H NMR (400 MHz, Chloroform-d) δ: 9.75 (d, J=11.1 Hz, 1H), 8.44 (d, J=11.2 Hz, 1H), 8.03 (s, 1H), 7.47 (d, J=8.3 Hz, 2H), 7.14~6.96 (m, 4H), 3.98 (s, 3H), 3.88 (s, 3H), 2.70 (s, 3H); ¹³C NMR (101 MHz, CDCl₃) δ: 195.75, 169.16, 158.72, 139.49, 136.62, 136.27, 136.07, 135.94, 131.38, 130.59, 129.16, 124.51, 115.95, 114.23, 114.08, 77.36, 77.25, 77.05, 76.73, 56.17, 55.41, 29.12. HRMS (ESI) calcd for C₂₀H₁₈NaO₃ [M+Na]⁺ 329.1148, found 329.1143.

  辅助材料(Supporting Information)  化合物3a~3q和4a~4d的¹H NMR以及¹³C NMR谱图.这些材料可以免费从本刊网站(http://sioc-journal.cn/)上下载.

  
  Dedicated to the 40th anniversary of Chinese Journal of Organic Chemistry.
  
• 1. [1]

     (a) Ward, R. S. Nat. Prod. Rep. 1995, 12, 183. (b) Thomson, R. H. Naturally Occurring Quinones IV. Recent Advances, 4th ed. Chapman & Hall, London, 1997.
     (c) Liu, X. L.; Zhao, Y.; Wang, W. W.; Wang, M. A.; Zhou, L. G. Chin. J. Org. Chem. 2017, 37, 2883(in Chinese).
     (刘鑫磊, 赵宇, 王卫伟, 王明安, 周立刚, 有机化学, 2017, 37, 2883.)

  2. [2]

     (a) Anthony, J. E. Angew. Chem., Int. Ed. 2008, 47, 452. (b) Reddy, R. A.; Baumeister, U.; Keith, C.; Tschierske, C. J. Mater. Chem. 2007, 17, 62.
     (c) Svoboda, J.; Novotna, V.; Kozmik, V.; Glogarova, M.; Weissflog, W.; Diele, S.; Pelzl, G. J. Mater. Chem. 2003, 13, 2104.
     (d) Christian, J.; Susann, G.; Helmut, H.; Brigitte, S. Naphthalene Compounds for Liquid-Crystalline Mixtures, WO 2017097400 A1.

  3. [3]

     For selected reviews: (a) Zhou, L.; Zhao, J.; Shan, T.; Cai, X.; Peng, Y. Mini-Rev. Med. Chem. 2010, 10, 977.
     (b) Ammar, Y. A.; Salem, M. A.; Fayed, Eman A.; Helal, M. H.; El-Gaby, M. S. A.; Thabet, H. K. Syn. Commun. 2017, 47, 1341. For selected examples:
     (c) Zhao, H.; Neamati, N.; Mazumder, A.; Sunder, S.; Pommier, Y.; Burke, T. R. J. Med. Chem. 1997, 40, 1186.
     (d) Ukita, T.; Nakamura, Y.; Kubo, A.; Yamamto, Y.; Takahashi, M.; Kotera, J.; Ikeo, T. J. Med. Chem. 1999, 42, 1293.
     (e) Wang, Y. H.; Zhao, J. Y. WO 2017202207, 2017.

  4. [4]

     For reviews: (a) Naphthalenes, Anthracenes, 9H-Fluorenes, and Other Acenens, Toyota, S.; Iwanaga, T. in Science of Synthesis (Houben-Weyl Methods of Molecular Transformations), Eds.: Siegel, J. S.; Tobe, Y., Vol. 45b, Thieme, Stuttgart, 2010, pp. 745~854.
     (b) de Koning, C. B.; Rousseau, A. L.; van Otterlo, W. A. L. Tetrahedron 2003, 59, 7.
     (c) Hein, S. J.; Lehnherr, D.; Arslan, H.; Uribe-Romo, F. J.; Dichtel, W. R. Acc. Chem. Res. 2017, 50, 2776.

  5. [5]

     (a) Miyaura, N.; Suzuki, A. Chem. Rev. 1995, 95, 2457.
     (b) Kotha, S.; Lahiri, K.; Kashinath, D. Tetrahedron 2002, 58, 9633.
     (c) Miyaura, N. Metal-Catalyzed Cross-Coupling Reactions of Organoboron Compounds with Organic Halides in Metal-Catalyzed Cross-Coupling Reactions (Eds. A. de Meijere, F. Diederich), WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim, 2004.
     (d) Li, Y.; Wang, Z. H. Org. Lett. 2009, 11, 1385.
     (e) Heffernan, G. D.; Jacobus, D. P.; Schiehser, G. A.; Shieh, H.-M.; Zhao, W. Preparation of Aryl Derivatives as Antimalarial Agents, WO 2014074778A1.
     (f) Kikuchi, Y.; Takahagi, H.; One, K.; Iwasawa, N. Chem. Asian J. 2014, 9, 1001.
     (g) Wang, Y. B.; Lin, Z. C.; Fan, H. L.; Peng, X. H. Chem. Eur. J. 2016, 22, 10382.

  6. [6]

     Hall, D. Boronic Acids:Preparation and Applications, Wiley-VCH, Weinheim, 2011.

  7. [7]

     For reviews, see: (a) Ishiyama, T.; Miyaura, N. J. Organomet. Chem. 2003, 680, 3.
     (b) Mkhalid, I. A. I.; Barnard, J. H.; Marder, T. B.; Murphy, J. C.; Hartwig, J. F. Chem. Rev. 2010, 110, 890.

  8. [8]

     For recent selected examples:
     (c) Yamamoto, T.; Morita, T.; Takagi, J.; Yamakawa, T. Org. Lett. 2011, 13, 5766.
     (d) Tang, W. J.; Keshipeddy, S.; Zhang, Y. D.; Wei, X. D.; Savoie, J. Patel, N. D.; Yee, N. K.; Senanayake, C. H. Org. Lett. 2011, 13, 1366.
     (e) Ros, A.; Estepa, B.; López-Rodríguez, R.; Álvarez, E.; Fernández, R.; Lassaletta, J. M. Angew. Chem., Int. Ed. 2011, 50, 11724.
     (f) Kawamorita, S.; Ohmiya, H.; Iwai, T.; Sawamura, M. Angew. Chem., Int. Ed. 2011, 50, 8363.
     (g) Kawamorita, S.; Miyazaki, T.; Ohmiya, H.; Iwai, T.; Sawamura, M. J. Am. Chem. Soc. 2011, 133, 19310.
     (h) Dai, H.-X.; Yu, J.-Q. J. Am. Chem. Soc. 2012, 134, 134.
     (i) Jiang, M.; Yang, H. J.; Fu, H. Org. Lett. 2016, 18, 5248.
     (j) Xu, Y. L.; Fang, H. Chin. J. Org. Chem. 2018, 38, 738(in Chinese).
     (徐玉良, 方浩, 有机化学, 2018, 38, 738.)

  9. [9]

     (a) Yamamoto, E.; Izumi, K.; Horita, Y.; Ito, H. J. Am. Chem. Soc. 2012, 134, 19997.
     (b) Yamamoto, E.; Ukigai, S.; Ito, H. Chem. Sci. 2015, 6, 2943.
     (c) Mo, F. Y.; Jiang, Y. B.; Qiu, D.; Zhang, Y.; Wang, J. B. Angew. Chem., Int. Ed. 2010, 49, 1846.

  10. [10]

      For reviews: (a) Wrackmeyer, B. Heteroat. Chem. 2006, 17, 188.
      (b) Melen, R. L. Chem. Commun. 2014, 50, 1161.
      (c) Buñuel, E.; Cárdenas, D. J. Eur. J. Org. Chem. 2016, 5446.
      (d) Issaian, A.; Tu, K. N.; Blum, S. A. Acc. Chem. Res. 2017, 50, 2598. For selected recent examples:
      (e) Yang, C.-H.; Zhang, Y.-S.; Fan, W.-W.; Liu, G.-Q.; Li, Y.-M. Angew. Chem., Int. Ed. 2015, 54, 12636.
      (f) Faizi, D. J.; Issaian, A.; Davis, A. J.; Blum, S. A. J. Am. Chem. Soc. 2016, 138, 2126.
      (g) Jiang, J. L.; Zhang, Z. Q.; Fu, Y. Asian J. Org. Chem. 2017, 6, 282.
      (h) Yuan, K.; Wang, S.-N. Org. Lett. 2017, 19, 1462.
      (i) Warner, A. J.; Churn, A.; McGough, J. S.; Ingleson, M. J. Angew. Chem., Int. Ed. 2017, 56, 354.
      (j) Kubota, K.; Yamamoto, E.; Ito, H. J. Am. Chem. Soc. 2013, 135, 2635.
      (k) Jiang, T.; Bartholomeyzik, T.; Mazuela, J.; Willersinn, J.; Bäckvall, J.-E. Angew. Chem., Int. Ed. 2015, 54, 6024.
      (l) Yu, S. J.; Wu, C. Z.; Ge, S. Z. J. Am. Chem. Soc. 2017, 139, 6526.
      (m) Zuo, Y.-J.; Chang, X.-T.; Hao, Z.-M.; Zhong, C.-M. Org. Biomol. Chem. 2017, 15, 6323.
      (n) Wang, H.-M.; Zhou, H.; Xu, Q.-S.; Liu, T.-S.; Zhuang, C.-L.; Shen, M.-H.; Xu, H.-D. Org. Lett. 2018, 20, 1777.
      (o) Lv, J. H; Zhao, B. L.; liu, L.; Han, Y.; Yuan, Y.; Shi, Z. Z. Adv. Synth. Catal. 2018, 360, 4054.

  11. [11]

      Liedtke, R.; Harhausen, M.; Fröhlich, R.; Kehr, G.; Erker, G. Org. Lett. 2012, 14, 1448. doi: 10.1021/ol300193e

  12. [12]

      Warner, A. J.; Lawson, J. R.; Fasano, V.; Ingleson, M. J. Angew. Chem., Int. Ed. 2015, 54, 11245. doi: 10.1002/anie.201505810

  13. [13]

      For selected examples from our group's work, please see: (a) Xiao, Y. J.; Zhang, J. L. Angew. Chem., Int. Ed. 2008, 47, 1903.
      (b) Liu, F.; Yu, Y. H.; Zhang, J. L. Angew. Chem., Int. Ed. 2009, 48, 5505.
      (c) Liu, F.; Qian, D. Y.; Li, L.; Zhao, X. L.; Zhang, J. L. Angew. Chem., Int. Ed. 2010, 49, 6669.
      (d) Zhou, L. J.; Zhang, M. R.; Li, W. B.; Zhang, J. L. Angew. Chem., Int. Ed. 2014, 53, 6542.
      (e) Zhang, Z.-M.; Chen, P.; Li, W. B.; Niu, Y. F.; Zhao, X. L.; Zhang, J. L. Angew. Chem., Int. Ed. 2014, 53, 4350.
      (f) Wang, Y. D.; Zhang, P. C.; Qian, D. Y.; Zhang, J. L. Angew. Chem., Int. Ed. 2015, 54, 14849.

  14. [14]

      For selected recent examples from other group's work, please see: (a) Pathipati, S. R.; van der Werf, A.; Eriksson, L.; Selander, N. Angew. Chem., Int. Ed. 2016, 55, 11863.
      (b) Kumari, A. L. S.; Swamy, K. C. K. J. Org. Chem. 2016, 81, 1425.
      (c) Zhang, H.; Yao, Q.; Lin, L. L.; Xu, C. R.; Liu, X. H.; Feng, X. M. Adv. Synth. Catal. 2017, 359, 3454.
      (d) Pathipati, S. R.; Eriksson, L.; Selander, N. Chem. Commun. 2017, 53, 11353.
      (e) Liu, S. N.; Yang, P.; Peng, S. Y.; Zhu, C. H.; Cao, S. Y.; Li, J.; Sun, J.-T. Chem. Commun. 2017, 53, 1152.
      (f) Zheng, Y.; Chi, Y. J.; Bao, M.; Qiu, L. H.; Xu, X. F. J. Org. Chem. 2017, 82, 2129.
      (g) Du, Q. W.; Neudçrfl, J.-M.; Schmalz, H.-G. Chem. Eur. J. 2018, 24, 2379.
      (h) Kardile, R. D.; Chao, T.-H.; Cheng, M.-J.; Liu, R.-S. Angew. Chem., Int. Ed. 2020, 59, 1.

  15. [15]

      X-ray data and ORTEP depiction for compounds 3b (CCDC 1870210).

  16. [16]

      Zhou, H.; Moberg, C. J. Am. Chem. Soc. 2012, 134, 15992. doi: 10.1021/ja3070717

  17. [17]

      Lv, J. H.; Zhao, B. L.; Yuan, Y.; Han, Y.; Shi, Z. Z. Nat. Commun. 2020, 11, 1316. doi: 10.1038/s41467-020-15207-x

  18. [18]

      (a) Yao, T. L.; Zhang, X. X.; Larock, R. C. J. Am. Chem. Soc. 2004, 126, 11164.
      (b) Yao, T. L.; Zhang, X. X.; Larock, R. C. J. Org. Chem. 2005, 70, 7679.
      (c) Liu, Y. H.; Zhou, S. L. Org. Lett. 2005, 7, 4609.

  19. [19]

      Thompson, A. L. S.; Kabalka, G. W.; Akula, M. R.; Huffman, J. W. Synthesis 2005, 36, 547.

  20. [20]

      Nakanishi, W.; Matsuyama, N.; Hara, D.; Saeki, A.; Hitosugi, S.; Seki, S.; Isobe, H. Chem. Asian J. 2014, 9, 1782. doi: 10.1002/asia.201402290

  21. [21]

      Li, Y.; Gao, L. X.; Han, F. S. Chem. Eru. J. 2010, 16, 7969. doi: 10.1002/chem.201000971

  22. [22]

      Yao, W. B. CN 107188773, 2017.

• 

  图 1  带有萘环的药物化学化合物

  Figure 1  Naphthalene-containing pharmaceuticals

  下载: 全尺寸图片 幻灯片
  

  图 2  硼化环化反应生成含硼官能团的萘衍生物

  Figure 2  Borylative cyclizations leading to boryl-functionalized naphthalene derivatives

  下载: 全尺寸图片 幻灯片
  

  图 3  底物扩展

  Figure 3  Scope of 2-(1-alkynyl)-2-alken-1-ones

  下载: 全尺寸图片 幻灯片
  

  图 4  3i的产物转化

  Figure 4  Synthetic transformation of 3i

  下载: 全尺寸图片 幻灯片

  表 1  反应条件优化^a

  Table 1.  Initial reaction discovery and condition optimization

  Entry	[B] (equiv.)	Solvent	Temp/℃	Yieldb/%
  1	BCl3 (2.0)	DCM	r.t.	50
  2	BBr3 (2.0)	DCM	r.t.	6
  3	BF3•OEt2 (2.0)	DCM	r.t.	0
  4	CatBCl (2.0)	DCM	r.t.	0
  5	BCl3 (2.0)	DCM	50	42
  6	BCl3 (2.0)	DCM	0	54
  7	BCl3 (2.0)	DCM	－20	64
  8	BCl3 (2.0)	DCM	－30	75
  9	BCl3 (2.0)	DCM	－40	75
  10	BCl3 (1.8)	DCM	－30	(85) 80c
  11	BCl3 (1.5)	DCM	－30	54
  12	BCl3 (1.8)	DCE	－30	71
  13	BCl3 (1.8)	CHCl3	－30	65
  14	BCl3 (1.8)	CCl4	－30	20
  15	BCl3 (1.8)	Toluene	－30	14
  16	BCl3 (1.8)	THF	－30	NR
  17	BCl3 (1.8)	1,4-Dioxane	－30	NR
  18	BCl3 (1.8)	DMF	－30	NR
  19	BCl3 (1.8)	DMSO	－30	NR
  a Reaction conditions: 1a (0.2 mmol), BCl3 (1.0 mol•L-1 in DCM), in solvent (2.0 mL), 8.0 h, under Ar. CatBCl=B-chlorocatecholborane. DIPEA=N, N-Diisopropylethylamine. NR=no reaction. b Determined by 1H NMR analysis using dibromomethane as an internal standard. c Isolated yield.

  下载: 导出CSV
•