Abstract
The unusual natural amino acid phosphorus containing didehydronorvaline (5) has been synthesized by consecutive treatment of the 4-bromo-2-butenal (1) with potassium cyanide and ammonium carbonate to the hydantoin (2), converted into the organophosphorus derivative 3, followed by enzyme-catalyzed hydrolysis of the diethoxyphosphinyl group to the phosphonic acid 4, and hydrolysis. The tetrahydro-1,2-azaphosphorine (8) and the protected didehydronorvaline derivatives 6, 7, 9, and 10, have been synthesized.