Enantioselective α-Alkenylation of Aldehydes with Boronic Acids via the Synergistic Combination of Copper(II) and Amine Catalysis
摘要:
The enantioselective alpha-alkenylation of aldehydes has been accomplished using boronic acids via the synergistic combination of copper and chiral amine catalysis. The merger of two highly utilized and robust catalytic systems has allowed for the development of a mild and operationally trivial protocol for the direct formation of alpha-formyl olefins employing common building blocks for organic synthesis.
使用铜/不饱和烃催化系统,烷基卤化物与烷基格氏试剂的交叉偶联可产生高达1230000的极高TON。烷基氟化物,氯化物,溴化物和甲苯磺酸盐都是合适的亲电子试剂,TOF高达31200 h –1使用烷基碘可以达到目的。在没有添加剂的情况下,该催化体系的副反应即还原,脱卤化氢(消除)和卤代烷的均偶联。看来该反应涉及烷基铜中间体的β-氢消除,从而产生烯烃和Cu-H物种,并且该过程既触发副反应又触发Cu催化剂的降解。形成的Cu–H可能促进歧化反应,从而促进烷基卤化物的还原,从而生成烷烃和Cu–X或Cu(0)的生成,这种歧化可以氧化添加到烷基卤化物中以产生烯烃,在某些情况下还可以是均偶联产物。1,3-丁二烯和苯丙炔等不饱和烃类添加剂通过抑制β-氢的消除在实现高效交叉偶联中起着重要作用,
Copper complexes generated in situ from CuCl2, alkylGrignardreagents, and 1,3‐dienes play important roles as catalytic active species for the 1,2‐hydroalkylation of 1,3‐dienes by alkylfluorides through CF bond cleavage. The alkyl group is introduced to an internal carbon atom of the 1,3‐diene regioselectively, thus giving rise to the branched terminal alkene product.
undergoes selective dimerization and alkylarylation with alkylfluorides and aryl Grignardreagents to give 1,6‐octadienes with alkyl and aryl groups at the 3‐ and 8‐positions, respectively, by the consecutive formation of three carbon–carbon bonds. The formation of an anionic nickel complex plays an important role in forming C−C bonds with alkylfluorides.
Ni/Photoredox-Catalyzed C(sp<sup>3</sup>)–C(sp<sup>3</sup>) Coupling between Aziridines and Acetals as Alcohol-Derived Alkyl Radical Precursors
作者:Sun Dongbang、Abigail G. Doyle
DOI:10.1021/jacs.2c09294
日期:2022.11.2
available C(sp3) precursors that afford valuable β-functionalized amines upon ring opening. In this article, we report a Ni/photoredox methodology for C(sp3)–C(sp3) cross-coupling between aziridines and methyl/1°/2° aliphatic alcohols activated as benzaldehyde dialkyl acetals. Orthogonal activation modes of each alkyl coupling partner facilitate cross-selectivity in the C(sp3)–C(sp3) bond-forming reaction:
Orthogonal C–O Bond Construction with Organogermanes
作者:Amit Dahiya、Avetik G. Gevondian、Franziska Schoenebeck
DOI:10.1021/jacs.3c01081
日期:——
involves the selective coupling of arylgermanes with alkyl alcohols (primary, secondary and tertiary) as well as carboxylic acids, tolerating otherwise widely employed coupling handles, such as aromatic (pseudo)halogens (C–I, C–Br, C–Cl, C–F, C–OTf, C–OFs), silanes and boronic acid derivatives. This unprecedented [Ge]-based C–O bond construction is rapid (15 min to few hours reaction time), air-tolerant
Compounds of the present invention, and pharmaceutically acceptable compositions thereof, are useful as modulators of ATP-Binding Cassette (“ABC”) transporters or fragments thereof, including Cystic Fibrosis Transmembrane Conductance Regulator (“CFTR”). The present invention also relates to methods of treating ABC transporter mediated diseases using compounds of the present invention.