SYNTHESIS AND REACTIONS OF OPTICALLY PURE CYCLOHEXYL(O-METHOXYPHENYL)PHOSPHINE-BORANE AND T-BUTYL-(O-METHOXYPHENYL)PHOSPHINE-BORANE

Cyclohexyl(o-methoxyphenyl) menthyloxyphosphine-borane and -butyl(o-me thoxyphenyl)menthyl-oxyphosphine-borane were prepared from dichlorocyc lohexylphosphine and t-butyldichlorophosphine by successive treatments with (-)-menthol, o-methoxyphenylmagnesium bromide, and borane-THF co mplex. The separated pure diastereomers of each of the compounds under went reaction with lithium naphthalenide to afford optically pure cycl ohexyl(o-methoxyphenyl)phosphine-borane and t-butyl(o-methoxyphenyl)ph osphine-borane, respectively. These secondary phosphine-boranes reacte d readily with various electrophiles in the presence of bases with vir tually net retention of configuration. A new chiral phosphine ligand, 2-bis[cyclohexyl(o-meth-oxyphenyl)phosphino]ethane was synthesized via the optically pure phosphine-boranes.