O-(2-Oxopyrrolidin-5-yl)trichloroacetimidates as Amidoalkylating Agents − Synthesis of (+)-Lentiginosine

Abstract

N-α-Hydroxyalkylamides 6a,b, readily available from L-tartrate, with trichloroacetonitrile furnish O-(2-oxopyrrolidin-5-yl)trichloroacetimidates 3a,b. α-Amido-alkylation studies of 3a,b with allyl-trimethylsilane and electron-rich benzene derivatives as C-nucleophiles afforded 5-allyl- and 5-aryl-2-pyrrolidinones 2a,b, 7a,b, and 8−10. The target compound (+)-1 and its epimer 15 were readily obtained from 1,5-diallyl-2-pyrrolidinones 2b and 7b, respectively, via ring-closing metathesis, amide group reduction, and CC-double bond hydrogenation. (© Wiley-VCH Verlag GmbH & Co KGaA, 69451 Weinheim, Germany, 2002)