| 5-Membered cyclic sulfonamides are important structural moieties existed in many biologically important natural products and pharmacologically active molecules,such as selective CRTh2 antagonists,HIV-1 inhibitor,inhibitor of Calpain.It’s highly important to develop catalytic and stereoselective methods to synthesis these structural moieties.The addition reaction including alkenylation reaction and ene reaction of styrene derivatives to 5-membered cyclic N-sulfonyl ketiminoesters was studied.1.The enantioselective alkenylation reaction of 5-membered cyclic N-sulfonyl ketiminoesters with styrenes was studied and the optimal reaction conditions were found after the scanning of transition metal,chiral ligand,solvent,temperature and so on.With 10 mol%of Ni-(S)-BINAP complex,the reaction proceeds efficiently in DCM at 100~oC,giving the yield from 35%to 99%and the enantioselectivity from 88%to 99%,After two-step conversion,the absolute configuration of the products was determined to be R through single crystal X-ray analysis.A series of 33 novel compounds were synthesized,including 7 new substrates of 5-membered cyclic N-sulfonyl ketiminoesters and 26 new products of 5-membered-cyclic sulfonamides.2.The enantioselective ene reaction of 5-membered cyclic N-sulfonyl ketiminoesters withα-methylstyrenes was studied and the optimal reaction conditions were found after the scanning of transition metal,chiral ligand,solvent,temperature and so on.With 10 mol%of Ni-(S)-SEGPHOS complex,the reaction proceeds efficiently in DCM at 100 ~oC,giving the yield from 68%to 99%and the enantioselectivity from 88%to 95%.A series of 28 novel compounds were synthesized,including 7 new substrates of 11-membered cyclic N-sulfonyl ketiminoesters and 17 new products of 5-membered cyclic sulfonamides. |
