Cooperative Organocatalysis for the Asymmetric γ Alkylation of α-Branched Enals
作者:Giulia Bergonzini、Silvia Vera、Paolo Melchiorre
DOI:10.1002/anie.201004761
日期:2010.12.10
α Branched leads to γ: The direct and enantioselective γalkylation of α‐substituted α,β‐unsaturated aldehydes under dienamine catalysis has been achieved. A cooperative catalysis system that involves dienamine activation of α‐branched enals and chiral Brønsted acid catalysis promotes an SN1‐alkylation pathway while ensuring complete γ‐site selectivity and high stereocontrol (see scheme; Bn=benzyl)
α分支导致γ:在二烯胺催化下,实现了α-取代的α,β-不饱和醛的直接和对映选择性γ烷基化。一个合作的催化系统涉及α-支链烯类的二烯胺活化和手性布朗斯台德酸催化,可促进S N 1烷基化途径,同时确保完全的γ位选择性和高度立体控制(参见方案; Bn =苄基)。
Fragrance composition
申请人:Kao Corporation
公开号:US09567550B2
公开(公告)日:2017-02-14
Provided is a fragrance composition containing a compound that is highly harmonious with other various fragrances and that can impart a stronger floral feeling by being blended. A fragrance composition containing 3,6-dimethyl-heptane-2-ol. The fragrance composition may further contain at least one selected from the group consisting of, for example, 7-methyloctane-3-ol, esters, carbonates, aldehydes, ethers, lactones, and alcohols other than 3,6-dimethylheptane-2-ol.
B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>: A New Class of Strong and Bulky Lewis Acid for <i>Exo</i>-Selective Intermolecular Diels–Alder Reactions of Unreactive Acyclic Dienes with α,β-Enals
Lewisacid B(C6F5)3 catalyzed the Diels–Alderreactions of multisubstituted open-chain dienes and α,β-enals to afford the desired products with high exo-selectivities are reported. The substituent effect of the dienes and dienophiles on the product’s stereoselectivity was thoroughly investigated, and it was found that most of the desired exo-Diels–Alder products could be obtained in good yields and
据报道,路易斯酸B(C 6 F 5)3催化多取代的开链二烯和α,β-烯醛的Diels-Alder反应,可提供所需的具有高外选择性的产物。彻底研究了二烯和亲二烯体对产物立体选择性的取代作用,发现大多数所需的exo -Diels-Alder产品可以高收率和高exo-立体选择性获得。