affording various tetrasubstituted thiophenes with aryl, alkenyl, alkyl, or silylgroup at the special position. The structural modification of alkyne substrates enabled the synthesis of diverse thiophenes to be achieved using the pyridinium 1,4-zwitterionic thiolates as the sulfur-containing building blocks. This approach is metal-free and catalyst-free.
Chiral Phosphine–Silver(I) Complex Catalyzed Enantioselective Interrupted Feist–Bénary Reaction with Ynones: The Aldol–Cycloisomerization Cascade
作者:Debarshi Sinha、Arnab Biswas、Vinod K. Singh
DOI:10.1021/acs.orglett.5b01468
日期:2015.7.2
Silver-catalyzed interrupted Feist-Benary reaction is described for the efficient enantioselective synthesis of dihydrofuran heterocycles. A new method has been developed for the silver(I)-(R)-BINAP complex mediated aldol cycloisomerization cascade reaction between ynones and 1,3-diketones to provide functionalized dihydrofurans with moderate to good yields (up to 95%) and good to excellent enantiomeric excess (up to 98%). The presence of an exocyclic double bond and hydroxy group in the dihydrofuran products provides wide scope for further structural manipulation.