Carbohydrate-substituted phosphines as new ligands for two-phase catalysis- synthesis and application

The synthesis and catalytic application of a new class of polar hydrophilic phosphines for two-phase catalysis is described in full detail. Contrary t o the well-known sulfonated phosphines the hydrophilic character of the lig ands is attributed to a neutral carbohydrate moiety. Two general routes for the synthesis of monosaccharide substituted triarylphosphines are presente d. In the first procedure protected halopyranoses and OH-substituted triphe nylphosphines were combined under phase transfer conditions to generate car bohydrate-substituted phosphines. In a second more efficient protocol, the palladium-catalyzed coupling of suitable haloaryl glycosides with diphenylp hosphine constitutes a new access to these ligands. The properties of the l igands in terms of solubility, surfactant activity, and partition between t wo non-miscible phases are discussed. In addition, superior catalytic perfo rmance compared to ionic hydrophilic ligands was demonstrated for important C-C coupling reactions such as the Suzuki, Heck, and hydroformylation reac tions. (C) 1999 Elsevier Science B.V. All rights reserved.