Selective synthesis of cis-2-vinyl-3-alkylaziridines and 3-pyrrolines from common intermediates (Z)-4-N-arylsulfonylaminoalk-2-en-1-ols

A simple method for the synthesis of both cis-2-vinylaziridines and 3-pyrrolines from common intermediate (Z)-4-(N-arylsulfonyl)amino-4-alkylbut-2-en-1-ols, is described. Palladium(0)-catalyzed reactions of methyl carbonates of the N-protected (Z)-4-amino-4-alkylbut-2-en-1-ols yield predominantly cis-3-alkyl-2-vinylaziridines. Alternatively, upon exposure to sodium hydride, methanesulfonates derived from N-protected (Z)-4-amino-4-alkylbut-2-en-1-ols give exclusively the corresponding 3-pyrrolines in high yields. A synthesis of biologically important (S)-3,4-dehydroproline is also presented.