The Enantioselective, Organocatalyzed Diels-Alder Reaction of 2-Vinylindoles with α,β-Unsaturated Aldehydes: An Efficient Route to Functionalized Tetrahydrocarbazoles
Prolinol catalysts: A highly enantio‐ and diastereoselective prolinol‐catalyzedDiels–Alderreaction of 2‐vinylindoles and α,β‐unsaturated aldehydes is developed (see scheme). This methodology allows the development of further applications of prolinols in asymmetric synthesis. The resulting densely functionalized enantiomerically pure tetrahydrocarbazoles are useful in the total synthesis of natural
An object of the present invention is to provide a method for manufacturing an optically active menthol having fewer steps, which generates less environmentally polluting waste because a catalytic reaction is involved in all of the steps, and is capable of saving a production cost. The present invention relates to a method for manufacturing an optically active menthol, including the following steps: A-1) asymmetrically hydrogenating at least one of geranial and neral to thereby obtain an optically active citronellal, B-1) conducting a ring-closure reaction of the optically active citronellal in the presence of an acid catalyst to thereby obtain an optically active isopulegol, and C-1) hydrogenating the optically active isopulegol to thereby obtain an optically active menthol.
A dual catalyst system provides the shortest pathway for l-menthol synthesis
作者:Hironori Maeda、Shinya Yamada、Hisanori Itoh、Yoji Hori
DOI:10.1039/c2cc16548a
日期:——
We have demonstrated that a combination of enantiopure 2-diarylmethylpyrrolidines and heterogeneous Pd/BaSO4 is an efficient catalytic system for the asymmetric hydrogenation of citral, specifically, a mixture of E-citral and Z-citral in any ratio, and that citronellal is obtained with high enantioselectivity. This dual catalyst system provides a new and more economical route to L-menthol.
An enantio- and diastereoselective approach to indoloquinolizidines in continuous flow
作者:Moreshwar B. Chaudhari、Prachi Gupta、Patricia Llanes、Leijie Zhou、Nicola Zanda、Miquel A. Pericàs
DOI:10.1039/d2ob01462a
日期:——
short synthesis of indoloquinolizidines. Using this approach, a highly enantioselective, solvent-free and rapid conjugate addition of dimethyl malonate to a diverse family of cinnamaldehydes in continuous flow, allowing the preparation of relevant oxodiesters in multigram amounts has been developed. The obtained Michael adducts have been used to complete an expedient diastereoselective synthesis of indoloquinolizidine
CATALYST FOR ASYMMETRIC HYDROGENATION AND METHOD FOR MANUFACTURING OPTICALLY ACTIVE CARBONYL COMPOUND USING THE SAME
申请人:Yamada Shinya
公开号:US20130217895A1
公开(公告)日:2013-08-22
The present invention provides a catalyst used for manufacturing an optically active carbonyl compound by selective asymmetric hydrogenation of an α, β-unsaturated carbonyl compound, which is insoluble in a reaction mixture, and a method for manufacturing the corresponding optically active carbonyl compound. Particularly, the invention provides a catalyst for obtaining an optically active citronellal useful as a flavor or fragrance, by selective asymmetric hydrogenation of citral, geranial or neral. The invention relates to a catalyst for asymmetric hydrogenation of an α, β-unsaturated carbonyl compound, which comprises: a powder of at least one metal selected from metals belonging to Group 8 to Group 10 of the Periodic Table, or a metal-supported substance in which the at least one metal is supported on a support; an optically active cyclic nitrogen-containing compound; and an acid, and also relates to a method for manufacturing an optically active carbonyl compound using the same.