N-光学活性的烷基化1-苄基-4-苯基-4,5-二氢咪唑活性烷基卤化物和在一系列缺电子的烯烃双极性亲和剂存在下用DBU处理如此形成的4,5-二氢咪唑鎓离子,构成终止于1,3-偶极环加成反应的``一锅''级联反应提供光学活性的吡咯并[1,2- a ]咪唑。在该级联反应中构建了如此形成的吡咯烷部分的三个键。环加成遵循内偶极子和亲偶极与方法抗偶极子的几何形状,并从苯基取代基衍生的面部选择性。观察到分子间和分子内的环加成模式。
N-光学活性的烷基化1-苄基-4-苯基-4,5-二氢咪唑活性烷基卤化物和在一系列缺电子的烯烃双极性亲和剂存在下用DBU处理如此形成的4,5-二氢咪唑鎓离子,构成终止于1,3-偶极环加成反应的``一锅''级联反应提供光学活性的吡咯并[1,2- a ]咪唑。在该级联反应中构建了如此形成的吡咯烷部分的三个键。环加成遵循内偶极子和亲偶极与方法抗偶极子的几何形状,并从苯基取代基衍生的面部选择性。观察到分子间和分子内的环加成模式。
Pyrrolo[1,2,3-de]quinoxalines: unexpected products from 1,3-dipolar cycloaddition of dihydroimidazolium ylides
作者:Raymond C.F Jones、James N Iley、Pedro M.J Lory、Simon C Coles、Mark E Light、Michael B Hursthouse
DOI:10.1016/s0040-4039(01)00617-7
日期:2001.6
4,5-Dihydroimidazoles undergo an N-alkylation and 1,3-dipolar cycloaddition cascade with unsaturated α-bromoketones, with subsequent eliminative ring-opening, recyclisation and tautomerisation to form unexpected hexahydropyrrolo[1,2,3-de]quinoxalines.
4,5-二氢咪唑与不饱和α-溴酮进行N-烷基化和1,3-偶极环加成反应,随后消除开环,环化和互变异构现象,形成意外的六氢吡咯并[1,2,3- de ]喹喔啉。
An Unexpected Stereochemical Course of Dihydroimidazolium Ylide Cycloadditions
作者:Raymond C. F. Jones、Shabana Rafiq、Mark R. J. Elsegood、Vickie McKee、Martin J. Slater
DOI:10.1002/asia.200900547
日期:2010.3.1
Turning the tables: We have observed an unexpected switch of cycloaddition mode from endo to exo for sulfone‐activated dipolarophiles with achiral dihydroimidazoliumylides to produce pyrrolo[1,2‐a]imidazoles, that may be related to the extra steric requirement of tetrahedral sulfur activating groups. This did not occur for chiral dihydroimidazoles, with just one exception amongst the examples reported
转台:我们已经观察到砜活化的双极性亲和剂与非手性二氢咪唑鎓叶立德意外地将环加成模式从内切向外切转换为吡咯并[1,2- a ]咪唑,这可能与四面体硫的额外空间需求有关激活组。对于手性二氢咪唑并没有发生这种情况,只有报道的实施例中有一个例外。
A rapid assembly of homochiral 2,3,4-trisubstituted pyrrolidines
作者:Raymond C.F. Jones、Kevin J Howard、John S Snaith
DOI:10.1016/s0040-4039(97)00111-1
日期:1997.3
The intramolecular 1,3-dipolar cycloaddition of homochiral dihydroimidazolium ylides, generated in situ, is the key reaction in a sequence that rapidly affords optically active 2,3,4-trisubstituted pyrrolidines suitably functionalised for further elaboration. (C) 1997 Elsevier Science Ltd.
Cycloaddition of homochiral imidazolinium ylides: A route to optically active pyrroloimidazoles
作者:Raymond CF Jones、Kevin J Howard、John S Snaith
DOI:10.1016/0040-4039(96)00113-x
日期:1996.3
The synthesis of either enantiomer of 1-benzyl-4-phenyl-2-imidazoline from phenylglycine is described. 'One-pot' generation and enantioselective 1,3-dipolar cycloaddition of homochiral azomethine ylides prepared from these imidazolines with a range of alkene dipolarophiles affords optically active hexahydropyrroloimidazole adducts.