Room Temperature Hydroalkylation of Electron-Deficient Olefins: sp3 C−H Functionalization via a Lewis Acid-Catalyzed Intramolecular Redox Event
摘要:
A practical method for the intramolecular hydroalkylation of electron-deficient olefins has been developed. The direct transformation of benzylic, tertiary, and sterically hindered secondary sp3 C-H bonds into C-C bonds under the action of a catalytic amount of a variety of Lewis acids is described. The mechanism of these transformations is proposed to involve a tandem hydride transfer/cyclization sequence.
Direct conjugate alkylation of α,β-unsaturated carbonyls by Ti<sup>III</sup>-catalysed reductive umpolung of simple activated alkenes
作者:Plamen Bichovski、Thomas M. Haas、Manfred Keller、Jan Streuff
DOI:10.1039/c5ob02631h
日期:——
The titanium(III)-catalysed cross-selective reductive umpolung of Michael-acceptors represents a unique direct conjugate β-alkylation reaction. It allows the cross-selective preparation of 1,6- and 1,4-difunctionalised building blocks without the requirement of stoichiometric organometallic reagents. In this full paper, the development and scope of the titanium(III)-catalysed cross-selective reductive
C–C Bond Formation via Copper-Catalyzed Conjugate Addition Reactions to Enones in Water at Room Temperature
作者:Bruce H. Lipshutz、Shenlin Huang、Wendy Wen Yi Leong、Guofu Zhong、Nicholas A. Isley
DOI:10.1021/ja309409e
日期:2012.12.12
Conjugate addition reactions to enones can now be done in water at roomtemperature with in situ generated organocopper reagents. Mixing an enone, zinc powder, TMEDA, and an alkyl halide in a micellar environemnt containing catalytic amounts of Cu(I), Ag(I), and Au(III) leads to 1,4-adducts in good isolated yields: no organometallic precursor need be formed.
Iridium-Catalyzed Enantioselective Allylic Substitution of Unstabilized Enolates Derived from α,β-Unsaturated Ketones
作者:Ming Chen、John F. Hartwig
DOI:10.1002/anie.201403844
日期:2014.8.11
We report Ir‐catalyzed, enantioselective allylic substitution reactions of unstabilized silyl enolates derived from α,β‐unsaturated ketones. Asymmetric allylic substitution of a variety of allylic carbonates with silyl enolates gave allylated products in 62–94 % yield with 90–98 % ee and >20:1 branched‐to‐linear selectivity. The synthetic utility of this method was illustrated by the short synthesis
我们报告了衍生自 α,β-不饱和酮的不稳定甲硅烷基烯醇化物的 Ir 催化的对映选择性烯丙基取代反应。用甲硅烷基烯醇化物对各种烯丙基碳酸酯进行不对称烯丙基取代得到烯丙基化产物,产率为 62-94%,ee为 90-98% ,支链至线性选择性 >20:1。抗癌剂 TEI-9826 的短合成说明了该方法的合成效用。
Syntheses of α,β-Unsaturated Carbonyl Compounds from the Reactions of Monosubstituted Ozonides with Stable Phosphonium Ylides
作者:Yung-Son Hon、Ling Lu、Rong-Chi Chang、Sheng-Wun Lin、Pei-Pei Sun、Chia-Fu Lee
DOI:10.1016/s0040-4020(00)00903-0
日期:2000.11
Ozonides derived from terminal alkenes reacted with 1.3 mol equiv. of stable phosphonium ylides to give (E)-α,β-unsaturated carbonyl compounds in good to excellent yields. No reducing agent is needed in the reaction. However, alkoxyalkyl-substituted ozonides afforded a mixture of (Z)- and (E)-α,β-unsaturated carbonyl compounds under similar condition. The E/Z isomeric ratio is affected by the position
Highly Enantioselective Conjugate Additions to α,β-Unsaturated Ketones Catalyzed by a (Salen)Al Complex
作者:Mark S. Taylor、David N. Zalatan、Andreas M. Lerchner、Eric N. Jacobsen
DOI:10.1021/ja044999s
日期:2005.2.1
Chiral (salen)Al complex 1a catalyzes the highly enantioselective conjugate addition of carbon- and nitrogen-based nucleophiles to acyclic α,β-unsaturatedketones. This methodology is tolerant of substantial variation of the ketone structure, providing access to a wide range of useful chiral building blocks in high yield and enantiomeric excess. Synthetic manipulations of the conjugate addition products