C₂-BIPNOR: An Easily Accessible Homologue of BIPNOR for Asymmetric Catalysis

Abstract

Under mild conditions at −78 °C, the McMurry coupling of the ( R )-2-formyl-1-phosphanorbornadiene 2 yields the enantiopure ( R P, S C, S C, R P ) diol 4, dubbed C 2 -BIPNOR. In boiling THF, the same reaction leads to the trans- alkene 6 . C 2 -BIPNOR is easier to prepare and to handle than BIPNOR while benefiting from the same configurational stability at phosphorus. It appears to have a wider range of catalytic applications than BIPNOR and, in one case (asymmetric Heck reaction), to be competitive with the best ligands proposed in the literature.