The stereoselectivealkenylation of unsaturated compounds by means of a (Z)-alkenyl sulfone-titanocene(II) system is described. Treatment of alkynes and (Z)-alkenyl methyl sulfones with the titanocene(II) reagent Cp2Ti[P(OEt)3]2 produced conjugated dienes. This alkenylation system is also applicable to polar CO bonds; the simple mixing of carbonyl compounds, (Z)-alkenyl methyl sulfones, and the titanocene(II)
描述了借助于(Z)-烯基砜-噻吩并茂(II)系统的不饱和化合物的立体选择性烯基化。用钛茂(II)试剂Cp 2 Ti [P(OEt)3 ] 2处理炔烃和(Z)-烯基甲基砜可制得共轭二烯。该烯基化体系也适用于极性C O键。羰基化合物,(Z)-烯基甲基砜和钛茂(II)试剂的简单混合形成了烯丙醇。烯基化的优点是它不需要制备烯基金属试剂,并且可以完全立体选择性地进行。
Electrochemical Nozaki–Hiyama–Kishi Coupling: Scope, Applications, and Mechanism
作者:Yang Gao、David E. Hill、Wei Hao、Brendon J. McNicholas、Julien C. Vantourout、Ryan G. Hadt、Sarah E. Reisman、Donna G. Blackmond、Phil S. Baran
DOI:10.1021/jacs.1c03007
日期:2021.6.30
practical using an electroreductive manifold. Although early studies pointed to the feasibility of such a process, those precedents were never applied by others due to cumbersome setups and limited scope. Here we show that a carefully optimized electroreductive procedure can enable a more sustainable approach to NHK, even in an asymmetric fashion on highly complex medicinally relevant systems. The e-NHK
最常用的 C-C 键形成方法之一是使用还原歧管,使卤乙烯与 Ni 和 Cr 催化的醛偶联(Nozaki-Hiyama-Kishi,NHK)变得更加实用。尽管早期研究指出了这种过程的可行性,但由于设置繁琐且范围有限,这些先例从未被其他人应用。在这里,我们展示了经过精心优化的电还原程序可以使 NHK 采用更可持续的方法,即使在高度复杂的医学相关系统上以不对称方式也是如此。当传统化学技术失败时,e-NHK 甚至可以使非规范底物类别(例如氧化还原活性酯)参与低负载量的 Cr。详细的动力学、循环伏安法、
Pd-Catalyzed Regioselective and Stereospecific Suzuki–Miyaura Coupling of Allylic Carbonates with Arylboronic Acids
The Pd-catalyzed Suzuki–Miyaura coupling reaction of unsymmetric 1,3-disubstituted secondary allylic carbonates with arylboronicacids has been developed in a wet solvent under a base-free system to afford allyl–aryl coupling products in a high level of isolated yields with complete regio- and E/Z-selectivities with good to excellent chemoselectivities. The coupling reaction of optically active allyl
enabled nickel‐catalyzed hydroalkenylation of aldehydes and styrenederivatives has been developed. The Brønsted acid acts as a proton shuttle to transfer a proton from the alkene to the aldehyde, thereby leading to an economical and byproduct‐free coupling. A series of synthetically useful allylic alcohols were obtained through one‐step reactions from readily available styrenederivatives and aliphatic