A variety of substituted benzob]furansare readily prepared in good to excellent yieldsunder the mild reaction conditions from o-(1-alkyn-ylphenoxy)-1-phenylethanone under phase-transfercatalysis (PTC). This methodology accommodatessimple experimental operations, inexpensive andenvironmentally benign catalysts, metal catalyst-free conditions, facile reagents and the possibility toconduct large-scale preparations. The developmentof carbon-carbon bond formation processes via anoverall structural isomerization represents the mostatom-economical approach.
The Lewis acid-catalyzed C H functionalization of 2-substituted azaarenes with N-sulfonyl-aldimines has been developed, which provides a rapid and efficient approach for synthesis of heterocycle-containing isoindolinones and isoindolines.
The first organocatalytic diastereo- and enantioselective Michael addition reaction of 4-substituted-pyrazolin-5-ones to nitroolefins has been developed with a chiral bifunctional thiourea as organocatalyst. A wide variety of desired multi-substituted pyrazolin-5-one derivatives with contiguous quaternary and tertiary stereocenters are smoothly obtained in very good yields (up to 98%) with excellent enantioselectivities (up to > 99% ee) and acceptable diastereoselectivities (up to 80:20). This experimentally simple process facilitates the access to various enantioenriched, multiply substituted pyrazolin-5-one derivatives, potential biologically active molecules, starting from readily available starting materials.
A practical method has been developed for the C-sulfinylation of enamides and enecarbamates using sodium phenylsulfinate/methyltrichlorosilane (PhSO2Na/MeSiCl3) as the sulfinylating reagent and N,N-dimethylacetamide (DMAc) as the Lewis base promoter. which allows for the preparation of a variety of N-protected-beta-sulfinylenamines in high yields and good stereoselectivities. The Lewis base is found to be important for both the in situ generation of the active sulfinylating species (PhSOCl) and the sulfinylation step.