A chiral N-linked C2-symmetric bidentate phosphoramidite (N-Me-BIPAM) was newly developed for the rhodium-catalyzed enantioselective addition of arylboronicacids to N-sulfonylimines. This ligand achieved high enantioselectivities in a range of 84–99% ee in additions of arylboronicacids to N-tosyl- and N-nosylarylaldimines.
Amine-Promoted Asymmetric (4+2) Annulations for the Enantioselective Synthesis of Tetrahydropyridines: A Traceless and Recoverable Auxiliary Strategy
作者:Pengfei Hu、Jian Hu、Jiajun Jiao、Xiaofeng Tong
DOI:10.1002/anie.201300526
日期:2013.5.10
without a trace: The in situ reaction of 2‐(acetoxymethyl)buta‐2,3‐dienoate and a secondary amine produces a 2‐methylene‐3‐oxobutanoate equivalent that can be used in asymmetric [4+2] annulations with N‐tosylimines to provide tetrahydropyridines in good to excellent yields and enantioselectivities. The amine is easily recovered and acts as a tracelessauxiliary.
A highlystereoselective access to 3-sulfinyl-substituted isoindolinones has been achieved by a tandem organocatalytic addition/cyclization reaction of 2-carbobenzyloxy-N-tosylbenzylidenimine with thiols and succeeding diastereoselective oxidation with MCPBA. First, enantioenriched isoindolinone N,S-acetals have been obtained through a dynamic kinetic asymmetric transformation induced by a bifunctional
The development of an intermolecular aza-Diels–Alder (DA) cycloaddition of sultines and imines is reported. By exploiting sultines as o-quinodimethane precursors and aryl imines as dienophiles in the presence of Cu(OTf)2, an aza-DA reaction proceeds to provide a wide variety of 3-aryl tetrahydroisoquionlines in moderate to excellent yield (up to 89%). The synthetic utility of these products was demonstrated
A Pd0complex can mediate dehydrogenative formation of 2,4-diene systems from γ,δ-unsaturated carbonyls in the presence of 2,6-DMBQ (2,6-dimethyl-1,4-benzoquinone), which undergo vinylogous addition to imines via auto-tandem Pd0-π-Lewis base catalysis. Both chemically inverse δ-regioselective aza-Morita–Baylis–Hillman adducts and α-regioselective normal ones are obtained switchably and stereoselectively