Improved Conditions for the Proline-Catalyzed Aldol Reaction of Acetone with Aliphatic Aldehydes
作者:Benjamin List、Alberto Martínez、Kristina Zumbansen、Arno Döhring、Manuel van Gemmeren
DOI:10.1055/s-0033-1340919
日期:——
The proline-catalyzed asymmetric aldol reaction between aliphatic aldehydes and acetone has, to date, remained underdeveloped. Challenges in controlling this reaction include avoiding undesired side reactions such as aldol condensation and self-aldolization. In recent years we have developed optimized conditions, which enable high yields and good to excellent enantioselectivities, and which are presented
Synthesis of Enantiomerically Pure β-Hydroxy Ketones via β-Keto Weinreb Amides by a Condensation/Asymmetric-Hydrogenation/Acylation Sequence
作者:Julian Diehl、Reinhard Brückner
DOI:10.1002/ejoc.201601202
日期:2017.1.10
an ester/amide exchange, and the use of the resulting β-hydroxy amide for the acylation of an organometallic compound. We shortened this route by showing that β-keto Weinreb amides are hydrogenated with up to 99 % ee in the presence of [Me2NH2]+[RuCl(S)-BINAP]2(µ-Cl)3}– (0.5 mol-%) at room temp./5 bar. These Weinreb amides were prepared by seemingly obvious yet unprecedented condensations of lithiated
Enantioselective synthesis of cyclic allylboronates by Mo-catalyzed asymmetric ring-closing metathesis (ARCM). A one-pot protocol for net catalytic enantioselective cross metathesis
作者:Jesper A. Jernelius、Richard R. Schrock、Amir H. Hoveyda
DOI:10.1016/j.tet.2004.06.017
日期:2004.8
Mo-catalyzed asymmetric ring-closing metathesis (ARCM) reactions are used to synthesize cyclic allylboronates of high optical purity (89% ee to >98% ee). A one-pot procedure involving formation of allylboronates, Mo-catalyzed ARCM and functionalization of the optically enriched cyclic allylboronates constitutes net asymmetric crossmetathesis (ACM). Structural modification of ARCM products include
Direct Asymmetric Aldol Reactions of Acetone Using Bimetallic Zinc Catalysts
作者:Barry M. Trost、Elliad R. Silcoff、Hisanaka Ito
DOI:10.1021/ol0161211
日期:2001.8.9
[reaction: see text] The enantioselective aldolreaction using a novel binuclear zinccatalyst of acetone with several aldehydes gave products in good yields (62-89%) with a high level of enantioselectivity (ee = 76-92%).
Preparation of the Enantiomerically Enriched Isomers of the Odorous Cyclic EthersClarycet ®,Florol ®, andRhubafuran ® by Enzymatic Catalysis
作者:Agnese Abate、Elisabetta Brenna、Giovanni Fronza、Claudio Fuganti、Francesco G. Gatti、Stefano Serra、Enrica Zardoni
DOI:10.1002/hlca.200490075
日期:2004.4
All the enantiomericallyenriched stereoisomers of Clarycet ® (1), Florol ® (2), and Rhubafuran ® (3) were prepared by biocatalysis routes. Their absolute configurations were established, and their olfactory properties were fully evaluated.