Stereoselective preparation of methylenecyclobutane-fused angular tetracyclic spiroindolines via photosensitized intramolecular [2+2] cycloaddition with allene
作者:Noriyoshi Arai、Takeshi Ohkuma
DOI:10.1016/j.tetlet.2019.151252
日期:2019.11
Irradiation of 3-(hexa-4,5-dienyl)indole derivatives in the presence of 3',4'-dimethoxyacetophenone by a high-pressure mercury lamp through Pyrex glass gave the corresponding [2+2] cycloaddition products stereoselectively in high yields. The major product was a methylenecyclobutane-fused angular tetracyclic spiroindoline derivative produced by the [2+2] cycloaddition through a parallel orientation
Cyclizations of 3,4-pentadien-1-yllithium reagents
作者:Jack K. Crandall、Timothy A. Ayers
DOI:10.1021/jo00037a008
日期:1992.5
A number of 3,4-pentadien-1-yllithium reagents were obtained by metal-halogen exchange. Certain of these intermediates undergo facile cyclization to the isomeric 1-cyclobutenylmethyllithium derivatives.