Chenistry of Natural Compounds, VoL 35~ No. ... Interesting synthetic possibilities are opened up by the discovery of the reaction of ketenylidenetriphenylphosphorane (61) with Ca-ignard ... O~',~'CH2)nOI3,21~ ~ R. ~,(CH2)nO~21~ 68, 69 70, 71 70 _.~ ~.._-,~CH2)sCH2OAc 72 b ...