Metallation reactions on 2,2′-bis(diphenylphosphinoyl)-1,1′-binaphthyl [BINAP(O)2]

Article abstract of DOI:10.1246/bcsj.76.1233

The behavior of BINAP(O)₂ upon treatment with lithium or magnesium amides under various conditions has been studied. With 2,2,6,6-tetramethylpiperidinomagnesium bromide, the ortho positions of opposed phenyl rings were selectively metallated, forming stable intermediates, while the use of lithium amides caused rearrangements with displacement of one diphenylphosphinoyl group and the formation of strained P-heterocycles (2, 5, 6) with unusual architectures. Monophosphine oxides 2 and 3a have been reduced to phosphines 13 and 14 in good yield, while substituted BINAP(O)₂ derivatives failed to give the desired diphosphines. The stereochemistry of six phosphine oxides (2, 3a, 5, 8, 9, 11a) and one phosphine (13) has been elucidated by crystal structure determinations.