Ruthenium<i>Lewis</i>Acid-Catalyzed Asymmetric<i>Diels-Alder</i>Reactions: Reverse-Face Selectivity for<i>α</i>,<i>β</i>-Unsaturated Aldehydes and Ketones
作者:Sirinporn Thamapipol、Bettina Ludwig、Céline Besnard、Christophe Saudan、E. Peter Kündig
DOI:10.1002/hlca.201600139
日期:2016.10
Acrolein, methacrolein, methylvinylketone, ethyl vinylketone, 3‐methyl‐3‐en‐2‐one, and divinyl ketone were coordinated to a cationic cyclopentadienyl ruthenium(II) Lewis acid incorporating the electron‐poor bidentate BIPHOP–F ligand. Analysis by NOESY and ROESY NMR techniques allowed the determination of conformations of enals and enones present in solution in CD2Cl2. The results were compared to
Broad-Spectrum Enantioselective Diels−Alder Catalysis by Chiral, Cationic Oxazaborolidines
作者:Do Hyun Ryu、Thomas W. Lee、E. J. Corey
DOI:10.1021/ja027468h
日期:2002.8.1
catalysts for Diels-Alder addition of cyclopentadiene to a wide variety of dienophiles. Adducts have been obtained in excellent yield and enantioselectivity from alpha,beta-unsaturated esters, lactones, and cyclic ketones. The absolute facial selectivity for each of these substrates follows a common pattern which differs from that observed with alpha,beta-enals. The different reaction channels can be
Enantioselective Diels-Alder Reaction of Acyclic Enones Catalyzed byallo-Threonine-Derived Chiral Oxazaborolidinone
作者:Ram Shanker Singh、Toshiro Harada
DOI:10.1002/ejoc.200500356
日期:2005.8
An allo-threonine-derived O-(p-biphenylcarbonyloxy)-B-phenyl-oxazaborolidinone is demonstrated to be a powerful and highly enantioselective Lewis acid catalyst for the enantioselective Diels–Alder reaction of simple acyclicenone dienophiles, expanding the scope of ketone dienophiles and dienes. With 10–20 mol % of the catalyst, the Diels–Alder adducts are obtained with up to 94 % ee and high endo
Asymmetric Lewis Acid-Catalyzed Diels−Alder Reactions of α,β-Unsaturated Ketones and α,β-Unsaturated Acid Chlorides
作者:Joel M. Hawkins、Mitch Nambu、Stefan Loren
DOI:10.1021/ol035524t
日期:2003.11.1
[reaction: see text] Conformational analysis, van der Waals attractions, and transition structure calculations are combined to design an asymmetric Lewis acid-catalyzed Diels-Alder reaction for simple acyclic alpha,beta-unsaturated ketones and alpha,beta-unsaturated acid chlorides, giving up to 83 and 92% ee, respectively. The two-point-binding chiral recognition mechanism, Lewis acid-Lewis base coordination