“Reductive ozonolysis” via a new fragmentation of carbonyl oxides

Authors

Chris Schwartz, University of Nebraska - LincolnFollow
Joseph Raible, University of Nebraska - Lincoln
Kyle Mott, University of Nebraska - Lincoln
Patrick Dussault, University of Nebraska-LincolnFollow

Date of this Version

September 2006

Comments

Published in Tetrahedron 62 (2006), pp. 10747–10752. doi:10.1016/j.tet.2006.08.092 Copyright © 2006 Elsevier Ltd. Used by permission. http://www.sciencedirect.com/science/journal/00404020.

Abstract

This account describes the development of methodologies for ‘reductive’ ozonolysis, the direct ozonolytic conversion of alkenes into carbonyl groups without the intermediacy of 1,2,4-trioxolanes (ozonides). Ozonolysis of alkenes in the presence of DMSO produces a mixture of aldehyde and ozonide. The combination of DMSO and Et₃N results in improved yields of carbonyls but still leaves unacceptable levels of residual ozonides; similar results are obtained using secondary or tertiary amines in the absence of DMSO. The influence of amines is believed to result from conversion to the corresponding N-oxides; ozonolysis in the presence of amine N-oxides efficiently suppresses ozonide formation, generating high yields of aldehydes. The reactions with amine oxides are hypothesized to involve an unprecedented trapping of carbonyl oxides to generate a zwitterionic adduct, which fragments to produce the desired carbonyl group, an amine, and ¹O₂.