A new useful method for the synthesis of dehydropeptide by the reaction of L-leucyl chloride with α-triethoxyphosphinimino-α-alkenoic acids, derived from ethyl α-azido-α-alkenoates and triethylphosphite, is described.
(hydroxy-, acetoxy-, or mesyloxy)-alkanoates with NaN3 or Et3N have been examined. The optimized procedure, in combination with subsequent reduction provides a general synthetic route to α-amino-α-alkenoic acid esters (9). The configuration of 8 and 9 have been shown to be of (Z)-geometry.
α,β-Unsaturated Carboxylic Acid Derivatives. XXI A Novel Synthesis of α-Dehydroamino Acid Derivatives by the Arbusov Reaction of α-Phosphoranylideneamino-2-alkenoates
The reaction of ethyl 2-azido-2-alkenoate with organic tervalent phosphorus reagent gave the corresponding 2-phosphoranylideneamino derivative as an stable intermediate. This transformed gradually at room temperature, or immediately on a silica-gel column to give the corresponding 2-phosphinylamino derivative in a good yield. The Arbusov reaction of the intermediate which occurred during the transformation