No abstract

N,N,N',N'-Tetrabromobenzene-1,3-disulfonamide was used as an efficient catalyst for the one-pot synthesis of pyrimidine derivatives in excellent yields from triethoxymethane, ammonium acetate, and various ketone derivatives at 100-110 8C under solvent-free conditions.

4H-Cromenos e diidropirano[3,2-c]cromenos são obtidos em rendimentos bons a excelentes através de um procedimento simples, brando e eficiente usando poli(N,N´-dibromo-N-etil-benzeno-1,3-dissulfonamida) [PBBS] e N,N,N´,N´-tetrabromobenzeno-1,3-dissulfonamida [TBBDA] como catalisadores. 4H-Chromenes and dihydropyrano[3,2-c]chromenes are obtained in good to excellent yields by a simple, mild and efficient procedure using poly(N,N'-dibromo-N-ethyl-benzene-1,3-disulfonamide) [PBBS] and N,N,N',N'-tetrabromobenzene-1,3-disulfonamide [TBBDA ] as catalysts.

Protecting-group-independent cross-coupling of α-alkoxyalkyl- and α-acyloxyalkyltrifluoroborates with aryl and heteroaryl bromides is achieved through application of photoredox/nickel dual catalysis. Reactions occur under exceptionally mild conditions, with outstanding functional group compatibility and excellent observed tolerance of heteroarenes. This method offers expedient access to protected secondary benzylic alcohol motifs bearing benzyl, pivaloyl, and N,N-diisopropylcarbamoyl protecting groups.