Regioselective Reduction of 3-Sulfonyl Glutarimides to 3,4-Dihydro-5-sulfonylpyridin-2-ones. Formal Synthesis of the Indolizidine 8a-epi-Dendroprimine
摘要:
Sodium borohydride regioselectively reduced various 3-sulfonyl glutarimides 1 to hydroxy piperidones 2, which were further dehydrated to 3,4-dihydro-5-sulfonylpyridin-2-ones 3 in the presence of boron trifluoride. Formal synthesis of 8a-epi-dendroprimine (4) possessing an indolizidine ring system has been accomplished via intramolecular radical cyclization of cyclic vinyl sulfone 5.