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Regioselective Asymmetric Formal (3+2) Cycloadditions of Nitrone Ylides from Isatins and Enals
Author(s) -
Chen YuRong,
Zhan Gu,
Du Wei,
Chen YingChun
Publication year - 2016
Publication title -
advanced synthesis and catalysis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.541
H-Index - 155
eISSN - 1615-4169
pISSN - 1615-4150
DOI - 10.1002/adsc.201600805
Subject(s) - regioselectivity , chemistry , nitrone , cycloaddition , iminium , enantioselective synthesis , catalysis , formal synthesis , crotonaldehyde , organic chemistry
A highly regio‐, diastereo‐ and enantioselective formal (3+2) cycloaddition reaction of nitrone ylides from isatins and α,β‐unsaturated aldehydes was developed via iminium catalysis in the presence of an additional base, furnishing a spectrum of 1′‐hydroxy‐3,2′‐pyrrolidinylspirooxindole frameworks. Interestingly, the regioselectivity could be finely switched in the reactions between nitrone ylides and crotonaldehyde by adding catalytic amounts of lithium perchlorate and copper(II) bromide.