Asymmetric Michael reactions of thiols with enones were catalyzed by a Sc(OTf)3–chiral bipyridine complex at room temperature in water without using any organic solvents, to afford the desired sulfides in high yields with high enantioselectivities.
Asymmetric Michael reactions and enantioselective protonations between enones and thiols were catalyzed by a Sc(OTf)3–chiral 2,2′-bipyridine complex in water. The remarkable governing of the enantioselectivity for simple introduction of protons despite their abnormally high mobility in water may provide us with new synthetic opportunities as well as significant chemical advances.
Iron catalyzed enantioselective sulfa-Michael addition: a four-step synthesis of the anti-asthma agent Montelukast
作者:James D. White、Subrata Shaw
DOI:10.1039/c4sc00051j
日期:——
catalyzes asymmetric addition of thiols to α,β-unsaturatedketones under mild conditions. The reaction (sulfa-Michael addition) produces β-thioketones in excellent yield and high enantiomeric excess from a wide range of aliphatic and aromatic thiols using chalcones and other conjugated enones as Michael acceptors. With α-substituted α,β-unsaturatedketones as acceptors, the addition shows strong preference
A Bifunctional Cinchona Alkaloid-Squaramide Catalyst for the Highly Enantioselective Conjugate Addition of Thiols to trans-Chalcones
作者:Le Dai、Su-Xi Wang、Fen-Er Chen
DOI:10.1002/adsc.201000334
日期:2010.9.10
A chiral squaramide catalysts‐promoted asymmetric sulfa‐Michael conjugated addition of thiols to trans‐chalcones is presented. Moderate to excellent yields and high enantioselectivities (up to 99% ee) were achieved under mild conditions.
β-dicarbonyl compounds. The use of these chiral iron–salen complexes as catalysts provides a new method for conducting these three important reactions under environmentally sustainable conditions. Iron(III)–salen complexes based on a chiral cis-2,5-diaminobicyclo[2.2.2]octane scaffold are used as catalysts for a variety of stereoselective reactions. High enantio- and diastereoselectivities can be achieved with