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
Palladium-Catalyzed Asymmetric Benzylation of 3-Aryl Oxindoles
作者:Barry M. Trost、Lara C. Czabaniuk
DOI:10.1021/ja1079755
日期:2010.11.10
we report palladium-catalyzedasymmetric benzylic alkylation with 3-aryl oxindoles as prochiral nucleophiles. Proceeding analogously to asymmetricallylicalkylation, asymmetric benzylation occurs in high yield and enantioselectivity for a variety of unprotected 3-aryl oxindoles and benzylic methyl carbonates using chiral bisphosphine ligands. This methodology represents a novel asymmetric carbon-carbon
The first Ni/Cu cocatalyzed asymmetric benzylation of aldimine esters has been developed. DFT calculations revealed that the strong electrophilicity of the η3-benzylnickel intermediate enabled the reaction to proceed smoothly under base-free conditions. The method was applied to the synthesis of BIRT-377 analogues, the key intermediate of PD154075 and CI-988.