A silver-catalyzed dehydrogenative cross-coupling reaction of substituted furans, thiophene, thioazole, and pyrrole 1a-e with dialkyl phosphites 2 was first developed to afford corresponding phosphonated products 3a-h with up to 89% yield and good regioselectivities. Moreover, an unprecedented coupling of various substituted pyridines 1f-k with dialkyl phosphites 2 using AgNO3 as a catalyst and K2S2O8 as an oxidant, followed by reduction with Na2S2O3, was also realized to furnish desired pyridine phosphonates 3i-q in satisfactory yields with good regioselectivities.
Manganese(III) Acetate Promoted Regioselective Phosphonation of Heteroaryl Compounds
[Structure: see text] A new method for direct phosphonation of thiazoles, furans, and pyrroles is introduced. Reactions of the heteroaryl compounds with dimethyl or diethyl phosphites and Mn(OAc)(3).2H2O under mild conditions give phosphonated products in high yield and good regioselectivity.