描述了铱催化的借氢过程在能够与高级醇形成 α-支化酮中的应用。为了促进该反应,邻位双取代的苯基和环丙基酮被认为是 CC 键形成的关键结构基序。在优化了关键催化步骤后,邻位二取代苯基产物可以通过反弗里德尔-克来福特酰化反应进一步操作,以产生合成有用的羧酸衍生物。相比之下,环丙基酮与几种亲核试剂进行同共轭加成,以提供进一步功能化的支化酮产物。
Iron-Facilitated Oxidative Radical Decarboxylative Cross-Coupling between α-Oxocarboxylic Acids and Acrylic Acids: An Approach to α,β-Unsaturated Carbonyls
The first Fe-facilitated decarboxylative cross-coupling reaction between α-oxocarboxylicacids and acrylic acids in aqueous solution has been developed. This transformation is characterized by its wide substrate scope and good functional group compatibility utilizing inexpensive and easily accessible reagents, thus providing an efficient and expeditious approach to an important class of α,β-unsaturated
DBU-Catalyzed Rearrangement of Secondary Propargylic Alcohols: An Efficient and Cost-Effective Route to Chalcone Derivatives
作者:Mrinal K. Bera、Rimpa De、Antony Savarimuthu、Tamal Ballav、Pijush Singh、Jayanta Nanda、Avantika Hasija、Deepak Chopra
DOI:10.1055/s-0040-1707909
日期:2020.10
A 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)-catalyzed rearrangement of diarylated secondarypropargylic alcohols to give α,β-unsaturated carbonyl compounds has been developed. The typical 1,3-transposition of oxy functionality, characteristic of Mayer–Schuster rearrangements, is not observed in this case. A broad substrate scope, functional-group tolerance, operational simplicity, complete atom economy
The combined use of a catalytic amount of InX3 (X = OTf and NTf2) and 1-butanol was found to be effective in formal alkyne–aldehyde metathesis. With this catalytic system, aromatic alkynes reacted with aromatic aldehydes to give chalcones in moderate to good yields. Alkynals were efficiently converted into 5- to 7-membered cyclic compounds by intramolecular alkyne–aldehyde coupling.
photoepoxidation of α,β-unsaturated ketones driven by visible light in the presence of tetramethylguanidine (3b), tetraphenylporphine (H2TPP), and molecular oxygen under mild conditions was revealed. The corresponding α,β-epoxy ketones were obtained in yields of up to 94% in 96 h. The reaction time was shortened to 4.6 h by flow synthesis. The mechanism related to singlet oxygen was supported by experiments
highly efficient electrophilic cyanation of boron enolates using readily available cyanating reagents, N‐cyano‐N‐phenyl‐p‐toluenesulfonamide (NCTS) and p‐toluenesulfonyl cyanide (TsCN), is reported. Various β‐ketonitriles were prepared by this new protocol, which has a remarkably broad substrate scope compared to existing methods. The present method also allowed efficient synthesis of β‐ketonitriles containing