Palladium-catalyzed allylic substitution between C-based nucleophiles and 6-azabicyclo[3.1.0]-hex-3-en-2-oxy derivatives: A new selectivity paradigm

[摘要] The reaction between alpha-hydroxy-(or alpha-acetoxy) cyclopenten-aziridines (6-azabicyclo[3.1.0]hex-3-en-2-ols or acetates) and C-based nucleophiles in the presence of Pd(0)-catalysis was investigated. In all the cases studied, the reaction was totally regio- and diastereo-selective, affording a single adduct in moderate to good yields. Specifically, attack of the nucleophile at position 3 of the cyclopentene moiety, anti to the vicinal oxy group, with vinylogous ring opening of the aziridine ring, was observed. When the carbon acid is a very acidic methylene (pK(a) (DMSO) <= 7.3), the resulting adduct is a zwitterion, resulting from an intramolecular proton transfer between the amino group and the carbon acid moiety taking place after the C-C bond formation. A plausible mechanism for this transformation is put forward. (C) 2020 Published by Elsevier Ltd.

[发布日期] 2020-12-18

[关键词] Palladium catalysis;Bicyclic aziridine;Tsuji-trost reaction