Deprotonation of 1,1 '-methylenebis4-tert-butyl-2-(diphenylphosphino)benzene and its analogues: synthesis and crystal structure of {5-Bu-t-24-Bu-t-2-(Ph2P)C6H3(Ph)CHC6H3P(Ph)K(OEt2)}(2)

摘要

Oxidation of 1,1'-methylenebis4-tert-butyl-2-(diphenylphosphino)benzene by H2O2 or S-8 in toluene affords two new PCP-type pincer ligands. The methylene group deprotonation in the new ligands as well as in their precursor by n-BuLi or LiCH2SiMe3 failed, while the methylene group in the precursor 1,1'-methylenebis4-tert-butyl-2-(diphenylphosphino)benzene was readily metallated by Lochmann Schlosser superbase to form the unstable potassium complex which in turn was readily transformed into new {5-Bu-t-2-4-Bu-t-2-(Ph2P)C6H3(Ph)CH-C6H3P(Ph)K(OEt2)}(2) complex due to phenyl group migration.