Versatile construction of functionalized tropane ring systems based on lactam activation: enantioselective synthesis of (+)-pervilleine B.

The halo-assisted intramolecular addition of silyl enol ethers with in situ activated lactams yielded (hydroxylated) 1-halo-8-azabicyclo[3,2,1]octane and 1-halo-9-azabicyclo[3,3,1]nonane ring systems, which provided an easy enantioselective access to 6ß-silyloxytropane-3-one, 3α,6ß-dihydroxytropane, and pervilleine B. The absolute configuration of the natural (-)-pervilleine B was determined to be 1R,3R,5S,6R.

Concise asymmetric total synthesis of 9-epi-sessilifoliamide J.

A 10-step asymmetric synthesis of 9-epi-sessilifoliamide J (20), together with sessilifoliamide J (6), has been accomplished from the key chiral building block 11 via a threo-selective vinylogous Mannich reaction and a Ley oxidation-SmI(2)-mediated coupling lactonization. The absolute configuration of the natural sessilifoliamide J was established.