jo5b01845_si_002.cif (15.23 kB)
N‑Heterocyclic Carbene-Catalyzed Diastereoselective Vinylogous Michael Addition Reaction of γ‑Substituted Deconjugated Butenolides
dataset
posted on 2015-12-18, 00:00 authored by Hao Guo, Fen Xing, Guang-Fen Du, Kuo-Wei Huang, Bin Dai, Lin HeAn efficient N-heterocyclic
carbene (NHC)-catalyzed
vinylogous Michael addition of deconjugated butenolides was developed.
In the presence of 5 mol % of the NHC catalyst, both γ-alkyl-
and aryl-substituted deconjugated butenolides undergo vinylogous Michael
addition with various α, β-unsaturated ketones, esters,
or nitriles to afford γ,γ-disubstituted butenolides containing
adjacent quaternary and tertiary carbon centers in good to excellent
yields with excellent diastereoselectivities. In this process, the
free carbene is assumed to act as a strong Brønsted base to promote
the conjugate addition.