Author/Authors :
Brodney، نويسنده , , Michael A. and Cole، نويسنده , , Marcus L. and Freemont، نويسنده , , Jamie A. and Kyi، نويسنده , , Stella and Junk، نويسنده , , Peter C. and Padwa، نويسنده , , Albert and Riches، نويسنده , , Andrew G. and Ryan، نويسنده , , John H.، نويسنده ,
Abstract :
We report the divergent effects of a 3a-methyl and 3a-phenyl substituent on the chemoselectivity and stereoselectivity of reduction of the enamide moiety of N-Boc-hexahydro-1H-indolin-5(6H)-ones. Under ionic reduction conditions (triethylsilane/trifluoroacetic acid) the enamide group of 3a-methyl-N-Boc-hexahydro-1H-indolin-5(6H)-one was reduced to afford exclusively a cis ring-fused product. For the 3a-phenyl substituted analogue more forcing conditions (sodium cyanoborohydride at pH 2–2.5) were required and resulted in the selective reduction of the enamide group to give a trans ring-fused product as well as reduction of the ketone group.
Keywords :
Hydroindole , furan , stereoselective , Enamide reduction , Intramolecular Diels–Alder cyclization
