Title

Study of the Rearrangements of Oxonium Ylides Generated from Ketals

Abstract

Intramolecular exposure of cyclic ketals to metal carbenoids generates a proposed oxonium ylide intermediate that subsequently rearranges to one of three general products. The product resulting from a 1,2-shift to the ketal carbon is favored by larger ketals that lack radical stabilizing groups. A bridged bicyclic structure is formed by competitive 1,2-shift to the exocyclic carbon of the ketal and is favored by smaller ketal ring sizes that possess radical-stabilizing groups. An alternative β-elimination pathway can also operate when neither of the 1,2-shift pathways are favored. The enol ether that is formed in this latter pathway rearranges easily to an isomeric dioxene.

Publication Date

6-1-1997

Journal Title

Journal of Organic Chemistry

Publisher

American Chemical Society

Digital Object Identifier (DOI)

10.1021/jo961896m

Document Type

Article

Rights

Copyright © 1997 American Chemical Society