Stereoselective synthesis of 1-amino-5-buty1-3-oxo- cyclohexane-1-carboxylic acid derivatives

摘要

Butyl-substituted 1-amino-3-oxocyclohexane- 1 -carboxylic acid derivatives have been pre-pared from 5,5-tethered dienes of (2R)-2,5-dihydro-2-isopropyl-3,6-dimethoxypyrazinein stereoselective synthesis. RCM reactions of the diene afforded a heterospirenone whichwas the substrate for the conjugated addition reaction with lithium dibutylcuprate. Hy-drolysis of the adduct provided cyclic a-amino acid derivatives. The absolute configurationat the new stereocentres were established by X-ray analyses.