F. Mathey et al., FROM 2H-PHOSPHOLES TO BIPNOR, A NEW EFFICIENT BIPHOSPHINE FOR ASYMMETRIC CATALYSIS, Journal of organometallic chemistry, 557(1), 1998, pp. 117-120
For many years now, we have studied the 1H-/2H-phosphole equilibrium a
nd its synthetic applications. On reaction with alkynes, 2H-phospholes
yield the corresponding 1-phosphanorbornadienes. As ligands of rhodiu
m(I), these phosphines show some potential in catalytic hydrogenation
and hydroformylation of alkenes. Starting from 3,3',4,4'-tetramethyl-1
,1'-biphospholyl and tolan, we have similarly obtained the correspondi
ng 2,2'-bis-(1-phosphanorbornadienyl) (BIPNOR) with two chiral, non-ra
cemisable, phosphorus atoms at the bridgeheads. The pure enantiomers o
f BIPNOR appear to be efficient ligands in asymmetric hydrogenation of
C=C and C=O double bonds. (C) 1998 Elsevier Science S.A. All rights r
eserved.