Expanding the field of phosphorus-containing fatty acid derivatives:: Synthesis of 1,2-oxaphospholene derivatives and alkenyl phosphonates from α-keto allenes

The first successful preparation of phosphorus-containing heterocyclic fatty acid derivatives is described. Reaction of the C-18 alpha-keto allene 1 and the C-18 alpha-keto chloroallene 2 with trimethyl phosphite gave the 1,2-oxaphospholene derivatives 4 and 6, respectively. Hydrolysis of 4 and 6 furnished the corresponding alkenyl phosphonate 5 and alkenyl chlorophosphonate 7, respectively. alpha-Chloro-alpha'-keto allene 3 gave the oxaphospholene derivative 8. The various intermediates and products were identified by a combination of spectroscopic and spectrometric techniques. (C) Wiley-VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2003.