Inverse electron demand asymmetric cycloadditions of cyclic carbonyl ylides catalyzed by chiral Lewis acids-Scope and limitations of diazo and olefinic substrates
Inverse electron demand asymmetric cycloadditions of cyclic carbonyl ylides catalyzed by chiral Lewis acids-Scope and limitations of diazo and olefinic substrates
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DOI：
10.1016/j.tet.2010.01.095
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发表时间：
2010-04-17
期刊：
影响因子：
2.1
通讯作者：
Baba, Toshihide
中科院分区：
文献类型：
--
作者：
Suga, Hiroyuki;Higuchi, Satoshi;Baba, Toshihide
Rh(2)(OAc)(4)催化邻甲氧基甲酰基α-重氮苯乙酮与环己基乙烯基醚之间的反电子1，3-偶极环加成反应具有较高的对映选择性(94-96%ee)。手性2，6-bis[(4S，5S)-4，5-diphenyl-2-oxazolinyl]pyridine.的Eu(OTf)(3)、Ho(OTf)(3)或Gd(OTf)(3)络合物(10mol%)能有效地催化反应与其他富含电子的偶极体的反应，如Ally！乙醇、2，3-二氢呋喃和丁基-叔丁基二甲基硅酮缩醛的对映选择性中等(60-73%ee)。2-(2-重氮基-1，3-二氧代烷基)苯甲酸甲酯与丁基或环己基乙烯基醚在联萘二亚胺(BINIM)-镍(II)络合物存在下发生的3-酰基-2-苯并苯并吡喃-4-甲酸酯的环加成反应也获得了良好的到高的对映体选择性(73-97%ee)。在相似条件下，2-(2-重氮基-1，3-二氧己基)苯甲酸甲酯与2，3-二氢呋喃的反应具有高度的内选择性和中等的对映选择性(ee=70%)。对于BINIM-Ni(II)催化的环己基乙烯基醚的反应，使用环氧吲哚作为3-酰基-2-苯并-4-吡喃-4-羟基的前体，发现手性Lewis酸可以作为不对称诱导的催化剂。1-重氮-2，5-戊二酮衍生物与丁基乙烯基醚或TBS乙烯基醚反应后，在(4S，5S)-4，5-Ph(2)-Lu(OTf)(3)络合物的催化下，得到了较好的不对称诱导(75-84%ee)。(C)2010爱思唯尔有限公司。保留所有权利。
High enantioselectivities (94-96% ee) were obtained for the inverse electron-demand 1,3-dipolar cyclo-additions between cyclohexyl vinyl ether and 2-benzopyrylium-4-olate generated via Rh(2)(OAc)(4)-catalyzed decomposition of o-methoxycarbonyl-alpha-diazoacetophenone. The reactions were effectively catalyzed by Eu(OTf)(3), Ho(OTf)(3), or Gd(OTf)(3) complexes (10 mol %) of chiral 2,6-bis[(4S,5S)-4,5-diphenyl-2-oxazolinyl]pyridine. The reactions with the other electron-rich dipolarophiles such as ally! alcohol, 2,3-dihydrofuran, and butyl-tert-butyldimethylsilylketene acetal showed moderate enanantioselectivities (60-73% ee). Good to high enantioselectivities (73-97% ee) were also obtained for the cycloadditions between 3-acyl-2-benzopyrylium-4-olates, generated from methyl 2-(2-diazo-1,3-dioxoalkyl)benzoates and butyl or cyclohexyl vinyl ethers, in the presence of binaphthyldiimine (BINIM)-Ni(II) complexes (10 mol %). Under similar conditions, the reaction between methyl 2-(2-diazo-1,3-dioxohexyl)benzoate and 2,3-dihydrofuran was highly endo-selective, and moderately enantioselective (70% ee). For the BINIM-Ni(II)-catalyzed reactions of cyclohexyl vinyl ether, the use of an epoxyindanone as the 3-acyl-2-benzopyrylium-4-olate precursor revealed that the chiral Lewis acid can function as a catalyst for asymmetric induction. The scope of the cyclic carbonyl ylides was extended to those generated from 1-diazo-2,5-pentanedione derivatives, which were reacted with butyl or TBS vinyl ether and catalyzed using the (4S,5S)-Pybox-4,5-Ph(2)-Lu(OTf)(3) complex to give good levels of asymmetric inductions (75-84% ee). (C) 2010 Elsevier Ltd. All rights reserved.