Falk Langer

Preparation of polyfunctional phosphines using zinc organometallics

Abstract The reaction of functionalized diorganozincs with chlorodiorganophosphines provides polyfunctional phosphines in good yields. Especially attractive is the hydroboration/boron-zinc exchange sequence which allows the conversion of functionalized olefins into polyfunctional phosphines in a one-pot procedure. Several new chiral phosphines have been prepared starting from readily available chiral olefins (terpenes) and their efficiency in asymmetric hydrogenation reactions has been evaluated.

Preparation and reaction of new dialkylzincs obtained by a boron-zinc transmetalation.

Abstract Various aliphatic organoboron derivatives were transmetalated to the corresponding dialkylzincs using diethyl- or dimethyl-zinc. This allows an access to zinc reagents not readily available by standard methods. Didecylzinc obtained by this methods adds with good enantioselectivity (83 % ee) to PhCHO in the presence of catalytic amounts of (1R, 2R)-1,2-bis-(trifluorosulfonamido)cyclohexane.

Preparation and reactions of functionalized chlorodiorganophosphine-borane complexes using organozinc reagents

Abstract A new efficient preparation of borane protected and free polyfunctional chlorodiorganophosphines using zinc organometallics is described. These chlorophosphine derivatives have been used for the preparation of several new chiral diphosphines of interest as ligands for transition metal catalysts.

A new efficient preparation of polyfunctional phosphines using zinc organometallics

Abstract The reaction of diorganozincs or organozinc halides with chlorophosphines (Ph n PCl 3-n ) produces polyfunctional phosphines in high yields. This method has been used to prepare several chiral phosphines in high enantiomeric purity.