We describe here the design and development of an organocatalyticPrinscyclization. In the presence of a confined chiral imidodiphosphoric acid catalyst, salicylaldehydes react with 3‐methyl‐3‐buten‐1‐ol to afford highly functionalized 4‐methylenetetrahydropyrans in excellent regio‐ and enantioselectivity. The extreme steric demand of the acid catalyst is key for the success of this transformation
Synthesis of Deoxyaminosugar Cyclohexyl-<scp>l</scp>-callipeltose and Its Diastereomer Using Pd-Catalyzed Asymmetric Hydroalkoxylation
作者:Sukhyun Lee、Young Ho Rhee
DOI:10.1021/acs.joc.9b01059
日期:2019.7.19
e, an aminodeoxysugar subunit of Callipeltoside A, was synthesized in six steps and 40% overall yield from readily available (S)-4-methylpent-4-en-2-ol and cyclohexyloxyallene. The signature step is represented by Pd-catalyzed asymmetric intermolecular hydroalkoxylation that generates the key dihydropyran intermediate upon combination with the ring-closingmetathesisreaction. Notably, an unnatural
Preparation of enantiomerically enriched flavor and fragrance components
申请人:Rhodia ChiRex, Inc.
公开号:US20020119909A1
公开(公告)日:2002-08-29
The present invention includes a process for enantioselective preparation of a non-racemic compound, which is either usable as a fragrance or flavor component or is convertible to a fragrance or flavor component by one or more additional reaction steps. The process includes the step of contacting either a substrate capable of forming a non-racemic compound by an enantioselective reaction and a co-reactant in the presence of a non-racemic catalyst, or a non-racemic or enantiopure substrate and a co-reactant, optionally in the presence of a racemic or non-racemic catalyst. The contacting is carried out at a temperature and length of time that is sufficient to produce the non-racemic compound with high optical purity. The process is used in stereoselective preparation of enantiomerically enriched intermediates useful in the preparation of non-racemic, chiral flavor and fragrance components.