InBr3-catalyzed stereoselective synthesis of 3,4-disubstituted hexahydro-1H-furo[3,4-c]pyran derivatives

An ?,δ-unsaturated alcohol tethered with a hydroxyl group, that is, (E)-2-styrylbutane-1,4-diol (1) undergoes a smooth bicyclization with various aldehydes in the presence of 10 mol % InBr₃ and at 0 °C to afford a novel series of hexahydro-1H-furo[3,4-c]pyran derivatives in good yields with high diastereoselectivity.     

Pd-catalyzed aerobic direct olefination of polyfluoroarenes

The first example of Pd-catalyzed aerobic direct olefination of polyfluoroarenes has been developed. The reaction makes use of molecular O₂ as terminal oxidant, and provides a cost-efficient and environmentally benign access to polyfluoroarene–alkene structures that are of interest in life and material sciences.     

BF3·OEt2-catalyzed synthesis of 1-(tetrahydropyran-3-yl)-1,3-dihydroisobenzofuran and trans-fused hexahydropyrano[3,2-c]chromene derivatives

A novel intramolecular Prins cyclization of (E)-5-(2-(hydroxymethyl)phenyl)pent-4-en-1-ol with aldehydes has been achieved using 10 mol % BF₃·Et₂O to produce 1-(tetrahydropyran-3-yl)-1,3-dihydroisobenzofuran derivatives in good to excellent yields with high selectivity. Similar type of coupling with salicylaldehydes provides the trans-fused hexahydropyrano[3,2-c]chromene derivatives in excellent yields.     

Copper(I) 3-methylsalicylate,an efficient catalyst for N-arylation of heterocycles under moderate reaction conditions

Copper(I) 3-methylsalicylate mediates N-arylation reactions of both aliphatic and aromatic heterocycles under moderate reaction conditions. Both electron rich and electron poor aryl bromides and a diverse set of N-heterocycles were allowed to react and gave N-arylation products in high yields which demonstrated the efficiency and utility of this catalyst.     

Operationally convenient method for preparation of sulfonamides containing α,α-difluoro-β-amino carbonyl moiety

We report here that the reactions of in situ generated unprotected α,α-difluoroenolates with various N-sulfonyl imines take place under operationally convenient conditions affording a novel type of fluorinated sulfonamides of high pharmaceutical potential. The reactions feature structural generality, excellent yields and can be easily scaled up for practical preparation of the target fluorine-containing sulfonamides.