Enantioselective synthesis of 2,3-disubstituted trans-2,3-dihydrobenzofurans using a Brønsted base/thiourea bifunctional catalyst
作者:Diego-Javier Barrios Antúnez、Mark D. Greenhalgh、Charlene Fallan、Alexandra M. Z. Slawin、Andrew D. Smith
DOI:10.1039/c6ob01326k
日期:——
The diastereo- and enantioselectivesynthesis of 2,3-disubstituted trans-2,3-dihydrobenzofuran derivatives (15 examples, up to 96 : 4 dr, 95 : 5 er) via intramolecular Michael addition has been developed using keto–enone substrates and a bifunctional tertiary amine–thiourea catalyst. This methodology was extended to include non-activated ketone pro-nucleophiles for the synthesis of 2,3-disubstituted
Enantioselective Copper-Catalyzed Reductive Michael Cyclizations
作者:Claire L. Oswald、Justine A. Peterson、Hon Wai Lam
DOI:10.1021/ol901560r
日期:2009.10.15
In the presence of siloxanes as stoichiometric reductants, chiral copper-bisphosphine complexes catalyze highly enantioselective reductive Michael cyclizations of substrates containing two alpha,beta-unsaturated carbonyl moieties. The diastereochemical outcome of these reactions is dependent upon whether biaryl- or ferrocene-based chiral bisphosphines are employed.