BIS(TRIPHENYLPHOSPHONIUMYLIDYL)PHOSPHANE

Bis(ylidyl)phosphanes can be prepared from ylides and dichlorophosphan es or from bis(ylidyl)phosphenium chlorides and organolithium compound s. By substituting in bis(ylidyl)phosphenium chlorides the chloride io n for more basic anions, a large variety of bis(ylidyl)phosphanes is a ccessible. They can be protonated at the ylidic carbon atoms, but alky lated and oxidized at the central phosphorus atom. As shown by P-31 NM R in solution and by Xray investigation of the crystal, the lone pair at the tervalent phosphorus is generally oriented synperiplanar to bot h phosphonio groups.