A novel, stereoselective silyl-directed Stevens [1,2]-shift of ammonium ylides.
[reaction: see text] The silyl group of 2-silylpyrrolidines such as 1 plays several critical roles: a stereochemical control element in a facially selective carbenoid addition to the ring nitrogen, a stereochemical "placeholder" during regioselective 1,2-migration with retention by the resulting spirocyclic ammonium ylide, and a hydroxyl surrogate for an eventual stereoselective Fleming-Tamao oxidation. This chemistry represents a novel use of the Stevens rearrangement and offers a short, enantioselective route to hydroxylated quinolizidines such as 3 from Boc-pyrrolidine.
Vanecko
John A
JA
Department of Chemistry, University of Utah, 315 S. 1400 East, Rm. 2020, Salt Lake City, Utah 84112-0850, USA.
West
F G
FG
D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000138:chemical synthesis; D006900:Hydroxylation; D011763:Pyrrolizidine Alkaloids / Q000138:chemical synthesis; D000644:Quaternary Ammonium Compounds / Q000737:chemistry; D011807:Quinolizines / Q000138:chemical synthesis*; D012821:Silanes / Q000737:chemistry; D013237:Stereoisomerism
D019086:Bridged Bicyclo Compounds, Heterocyclic; D011763:Pyrrolizidine Alkaloids; D000644:Quaternary Ammonium Compounds; D011807:Quinolizines; D012821:Silanes