Hafnium Trifluoromethanesulfonate [Hf(OTf)₄]-Catalyzed Conjugate ­Addition of Indoles to α,β-Enones

Abstract

Hafnium trifluoromethanesulfonate [Hf(OTf)₄]- and scandium trifluoromethanesulfonate [Sc(OTf)₃]-catalyzed conjugated addition of 3-position of indoles to several enones proceeded in acetonitrile as solvent. Especially, Hf(OTf)₄ exhibited high catalytic ­activity and gave the conjugate addition product in good yield.

Key words

hafnium trifluoromethanesulfonate - conjugate additions - Lewis acids - indoles - enones - catalysis

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