Affiliation:
1. Department of Chemistry New York University 100 Washington Square East New York NY 10003 USA
2. Leiden Institute of Chemistry Leiden University Einsteinweg 55 2300 RA Leiden The Netherlands
Abstract
AbstractA single acyloxy group at C‐2 can control the outcome of nucleophilic substitution reactions of pyran‐derived acetals, but the extent of the neighboring‐group participation depends on a number of factors. We show here that neighboring‐group participation does not necessarily control the stereochemical outcome of acetal substitution reactions with weak nucleophiles. The 1,2‐trans selectivity increased with increasing reactivity of the incoming nucleophile. This trend suggests the intermediacy of both cis‐fused dioxolenium ions and oxocarbenium ions in the stereochemistry‐determining step. In addition, as the electron‐donating ability of the neighboring group decreased, the preference for the 1,2‐trans products increased. Computational studies show how the barriers for the ring‐opening reaction on the dioxolenium ions and the transition states to provide the oxocarbenium ions change with the electron‐donating capacity of the C‐2‐acyloxy group and the reactivity of the nucleophile.
Funder
National Institute of General Medical Sciences
Nederlandse Organisatie voor Wetenschappelijk Onderzoek
H2020 European Research Council
National Science Foundation
National Institutes of Health
Subject
General Chemistry,Catalysis,Organic Chemistry
Cited by
2 articles.
订阅此论文施引文献
订阅此论文施引文献,注册后可以免费订阅5篇论文的施引文献,订阅后可以查看论文全部施引文献