ORGN 76 |
| Oxocarbenium ions are reactive intermediates in many important synthetic transformations, including glycosylation, Prins–Pinacol cyclizations, and oxa-Pictet–Spengler reactions. We have recently reported a highly enantioselective variant of the acyl-Pictet–Spengler reaction, in which N-acyliminium ions undergo cyclization in the presence of a chiral thiourea catalyst. The extension of this strategy to reactions involving oxocarbenium ions has led to the discovery of an enantioselective oxa-Pictet–Spengler reaction. Catalyst and reaction development, as well as substrate scope, will be described. Experiments probing the role of the catalyst in promoting reactions of highly electrophilic intermediates will also be presented.
|
|
Asymmetric Reactions and Syntheses
1:00 PM-5:00 PM, Sunday, 10 September 2006 Moscone Center -- Room 131, Oral
Division of Organic Chemistry |