Title

A Mechanistic Investigation into the Zinc Carbenoid-mediated Homologation Reaction by DFT methods: Is a Classical Donor-Acceptor Cyclopropane Intermediate Involved?

Abstract

An extensive density functional theory (DFT, M05-2X) investigation has been performed on the zinc carbenoid-mediated homologation reaction of β-keto esters. The mechanistic existence of a classical donor−acceptor cyclopropane intermediate was probed to test the traditional school of thought regarding these systems. Calculations of the carbenoid insertion step, following enolate formation, unmasked two possible pathways. Pathway B was shown to explain the proposed, but spectroscopically unobservable donor−acceptor cyclopropane intermediate, while the second (pathway A) reveals an alternative to the classical intermediate in that a cyclopropane transition state leads to product.

Publication Date

11-1-2010

Journal Title

Journal of Organic Chemistry

Publisher

American Chemical Society

Digital Object Identifier (DOI)

10.1021/jo101590t

Document Type

Article

Rights

Copyright © 2010, American Chemical Society