Binap, (A+-)- → Diphenylphosphine

Participants

Reaction Steps

U.S. Pat. No. 5,399,771 discloses a process for preparing BINAP starting from enantiomerically pure binaphthol which is firstly converted into the corresponding bis(trifluoro-methanesulfonate). BINAP is subsequently obtained by nickel-catalysed coupling with diphenylphosphine. Disadvantages of this process are the high price and the difficulty of industrial handling of the sensitive and extremely aggressive trifluoromethanesulfonic anhydride in the preparation of binaphthol bis(trifluoromethane-sulfonate). The use of other trifluoromethanesulfonic acid derivatives such as trifluoromethanesulfonyl fluoride or chloride is also difficult in process engineering terms due to the high volatility of the compounds (b.p.=−20° C. and 32° C., respectively).

Provenance & Evidence