Asymmetric Synthesis Of α-Amino Acids Via Heterocyclic Compounds As Pre-function

Optically activeα-amino acids are valuable compounds of high interests of chemical society not only owing to their remarkable pharmacological and biological activities but also for their role as a chiral auxiliary in asymmetric synthesis and an investigative topographic probe for bioactive conformations of peptides and the mechanisms of enzyme reactions. Besides there is a growing demand for optically active, ideally enantiomerically pure, uncommon amino acids resulting from the recent progresses in molecular biology and protein engineering technologies.Heterocyclic compounds as latent functionality were commonly used in organic synthesis. Furan and its derivatives are the most common ones. Chiralα-alkylfurfurylamines are very useful building blocks for the syntheses of a considerable number of nitrogen containing natural products, such asα-amino acids,β-lactams, indolizilines, quinolizidines and piperidine alkaloids.In this article four camphor sulfonamides were synthesized from natural camphor, and four camphor derived imines which haven't been published were easily prepared by condensing the sulfonamides with 2-furfuryl amine respectively.Optically activeα-alkylfurfurylamines were asymmetric synthesized via the asymmetric alkylation of one of the four camphor imines N-isopropyl-(d)-10-camphor sulfonamide -1-(2-fural) imines by sec-butyllithium. The diastereoselectivities ranging from 11-98% were determined by ~1H NMR spectra of the alkylation products. Stereoconformation R was determined by comparing with literature and other analysis databases.Finally optically active phenylalanine were synthesized by sodium periodate -rhodium(III) chloride mixture via oxidation of benzylation product of N-isopropyl-(d)-10-camphor sulfonamide -1-(2-fural) imines.