A practical chiral bicyclic thioglycolate lactam auxiliary for stereoselective quaternary carbon formation.
[reaction: see text] Chiral bicyclic thioglycolate lactams may be prepared in three steps from inexpensive commercial materials. The resulting lactams may be alkylated three times, twice using basic enolization and once using reductive enolization, to form alpha-quaternary carboxylic acid derivatives in high yield and with high diastereoselectivity. The alkylation products may be cleaved under either acidic or reductive conditions to furnish either carboxylic acids or primary alcohols, respectively.
Arpin
Azélie
A
Department of Chemistry, McGill University, 801 Sherbrooke St. West, Montreal, QC, Canada H3A 2K6.
Manthorpe
Jeffrey M
JM
Gleason
James L
JL