A New Family of Cinchona-Derived Bifunctional Asymmetric Phase-Transfer Catalysts: Application to the Enantio- and Diastereoselective Nitro-Mannich Reaction of Amidosulfones
作者:Kayli M. Johnson、Matt S. Rattley、Filippo Sladojevich、David M. Barber、Marta G. Nuñez、Anna M. Goldys、Darren J. Dixon
DOI:10.1021/ol300779x
日期:2012.5.18
family of bifunctional H-bond donor phase-transfer catalysts derived from cinchona alkaloids has been developed and evaluated in the enantio- and diastereoselective nitro-Mannich reaction of in situgenerated N-Boc-protected imines of aliphatic, aromatic, and heteroaromatic aldehydes. Under optimal conditions, good reactivity and high diastereoselectivities (up to 24:1 dr) and enantioselectivities (up to
Biodegradable Chitosan-Derived Thioureas as Recoverable Supported Organocatalysts - Application to the Stereoselective Aza-Henry Reaction
作者:José M. Andrés、Fernando González、Alicia Maestro、Rafael Pedrosa、María Valle
DOI:10.1002/ejoc.201700582
日期:2017.7.7
polymers. These organocatalysts are able to promote the enantioselective aza-Henry reaction with good yields and enantioselection. The activity and stereoselectivity of those materials are dependent on the accessibility of the reactants to the active site, and they increase with the length of the tether connecting the thiourea and the biopolymer. The best catalyst can be recovered and recycled for