Dearomative (3 + 2) Cycloadditions of Unprotected Indoles
作者:Bram Ryckaert、Jan Hullaert、Kristof Van Hecke、Johan M. Winne
DOI:10.1021/acs.orglett.2c01214
日期:2022.6.17
The (3 + 2) cycloaddition of various indoles with a dithioallyl cation affords dearomatized cyclopentannulated adducts, with complete control of regioselectivity and excellent chemo- and diastereoselectivity. The success of the reaction critically relies on the use of an excess of very strong Brønsted acid, which paradoxically prevents carbocationic side reactions. The reaction tolerates sensitive
Catalytic Asymmetric Dearomatization of 2,3-Disubstituted Indoles by a [4 + 2] Cycloaddition Reaction with In Situ Generated Vinylidene <i>ortho</i>-Quinone Methides: Access to Polycyclic Fused Indolines
作者:Amit Shikari、Chandrakanta Parida、Subhas Chandra Pan
DOI:10.1021/acs.orglett.4c00557
日期:——
A protocol of enantioselective dearomatization of 2,3-disubstitutedindoles by an organocatalytic intermolecular (4 + 2) cycloaddition reaction with in situ generated vinylidene ortho-quinone methide has been documented. A wide range of polycyclic 2,3-fused indolines containing vicinal quaternary carbon stereocenters was readily prepared in high yields and with excellent diastereo- and enantioselectivities