Green Construction Of P(O)-S Bonds And Sp~3C-P(O) Bonds By Dehydrogenative Strategy

Because of the unique properties and wide applications,continuing efforts have been devoted to developing simpler and cleaner methods for the synthesis of organophosphorus compounds.Among theses methods for preparing organophosphorus compounds,dehydrogenation cross-coupling reaction and Hydrogen-borrowing strategis are the most effective methods.In this paper,a palladium-catalyzed P(O)-H/S-H dehydrogenative coupling to prepare phosphorothioate compounds and a base-mediated dehydrative coupling to construct sp3C-P bond are described.The specific contents and the results come as follows:(1)A dehydrogenative coupling of P(O)-H compounds with RS-H compounds was achieved by palladium catalysis,producing the corresponding phosphorothioates in high yields.The reaction showed good functional-group tolerance,a variety of groups like ester,ether,F,Cl,Br,trifluoromethyl,nitro and ect.all could be compatible in the current catalytic system.Phosphinates,phosphites and secondary phosphine oxides all successfully coupled with aliphatic or aromatic RS-H compounds.By using the present strategy,the value-added P-chiral phosphorothioates were also synthesized stereo-selectively with configuration at phosphorus group being intact.The active reation intermediates were isolated and characterized,thus the mechanism was well elucidated.(2)A hydrogen-borrowing strategy was developed to construct sp-3C-P(O)bonds.By using the cheap,low toxic phenylethyl alcohols and P(O)-H compounds as raw materials,various organic phosphorus compounds containing sp3C-P(O)bond were produced in good to high yields via dehydrative coupling mediated by only a base.The reaction proceeds under a relatively mild reaction conditions,providing a green and efficient choice for preparing orgnophosphorus compounds.