SYNTHESIS AND SOME REACTIONS OF A 2,2'-BIPHOSPHOLYL

Article abstract of DOI:10.1016/0022-328X(86)80496-X

1,1'-Diphenyl-3,3',4,4'-tetramethyl-2,2',5,5'-tetrahydro-2,2'-biphosphole obtained by reductive dimerization of the appropriate phosphole has been converted into the corresponding 2,2'-biphosphole by P-bromination followed by dehydrobromination of the resulting P,P'-tetrabromo compound with α-picoline.This 2,2'-biphosphole gives two isomeric P-sulfides upon reaction with sulfur, and a Mo(CO)4 chelate upon reaction with Mo(CO)6.Cleavage of the two P-phenyl bonds by lithium in THF yields the corresponding biphospholyl anion, which is converted into a mixture of two isomeric bis(η⁵,η⁵-2,2'-diphosphafulvalene)diirons by treatment with FeCl2.The reaction of Mn2(CO)10 in boiling xylene affords a mixture of three complexes, including a (η⁵,η⁵-2,2'-diphosphafulvalene)hexacarbonyldimanganese produced by thermal cleavage of the two P-Ph bonds.Under CO pressure there is a <1,5> P --> C shift of the two phenyl groups, leading to formation of (η⁵,η⁵-3,3'-diphenyl-2,2'-diphosphafulvalene)hexacarbonyldimanganese.