Unusual reaction of 8-chloro-2-cyclohexyl-4-phenylbenzo[e]-1,2-oxaphosphinine-2-oxide with tetramethylenebis(magnesium bromide)

Abstract

The reaction of 8-chloro-2-cyclohexyl-4-phenylbenzo[e]-1,2-oxaphosphinine-2-oxide with ethyl- and phenylmagnesium bromides and tetramethylenebis(magnesium bromide) is a versatile approach to the synthesis of unsymmetrical phosphine oxides. With the latter Grignard reagent, an unusual phosphorus-carbon cleavage also occurs to yield a pentacoordinate phosphorus derivative, 2,3,8,9-bis(4-chlorobenzo)-6-cyclohexyl-6,9-diphenyl-1,7-dioxa-6-phosphaspiro[5.5]deca-1,9-diene. © 2008.