A radical-mediated oxidative cross-coupling of readily accessible α-alkylated styrenes with 1,3-dicarbonyl compounds utilizing a combination of Cu(OAc)2 and air as a catalytic system is described. Rather than requiring α-halocarbonyl compounds, this efficient approach enables direct installation of tertiary functionalized alkyl motifs to olefins with simple carbonyl derivatives. The novel protocol
Lewis Acid Catalyzed Transfer Hydromethallylation for the Construction of Quaternary Carbon Centers
作者:Johannes C. L. Walker、Martin Oestreich
DOI:10.1002/anie.201909852
日期:2019.10.21
of this surrogate in the hydromethallylation of electron-rich styrene derivatives provided sterically congested quaternary carbon centers. The reaction proceeds by C(sp3 )-C(sp3 ) bond formation at a tertiary carbenium ion that is generated by alkene protonation. The possibility of two concurrent mechanisms is proposed on the basis of mechanistic experiments using a deuterated surrogate.
Copper-Catalyzed Diastereo- and Enantioselective Desymmetrization of Cyclopropenes: Synthesis of Cyclopropylboronates
作者:Alejandro Parra、Laura Amenós、Manuel Guisán-Ceinos、Aurora López、José Luis García Ruano、Mariola Tortosa
DOI:10.1021/ja510419z
日期:2014.11.12
A novel Cu-catalyzed diastereo- and enantioselective desymmetrization of cyclopropenes to afford nonracemic cyclopropylboronates is described. Trapping the cyclopropylcopper intermediate with electrophilic amines allows for the synthesis of cyclopropylaminoboronic esters and demonstrates the potential of the approach for the synthesis of functionalized cyclopropanes.
描述了一种新型的 Cu 催化的环丙烯的非对映选择性和对映选择性去对称化,以提供非外消旋的环丙基硼酸酯。用亲电胺捕获环丙基铜中间体可以合成环丙基氨基硼酸酯,并展示了该方法合成功能化环丙烷的潜力。
Silver(I)-Catalyzed Diastereoselective Hydroborylation of Cyclopropenes
explored by control experiments, providing a number of key insights. The kinetic process followed by 1H NMR indicated that the reaction was finished in 15 min. Furthermore, the mechanism of silver(I)-catalyzed hydroborylation of cyclopropenes was proposed, with the protonation by methanol as the rate-determining step.
在环丙烯与 B 2 pin 2的氢硼化中开发了一种有效的 (NHC)AgCl 催化,以立体选择性方式产生各种环吡基硼酸酯,可以轻松地转化为通用环丙烷的构建。该方案在露天气氛中的温和反应条件下有效地发挥作用,并且很容易在克规模上应用。这种新颖的方法还通过对照实验进行了详细探索,提供了许多关键见解。1 H NMR的动力学过程表明反应在 15 分钟内完成。此外,提出了银(I)催化环丙烯的硼氢化反应机理,其中甲醇质子化作为速率决定步骤。
Electrochemical Radical Retro-Allylation of Homoallylic Alcohols with Sulfonyl Hydrazides
We report herein the first examples of electrochemical radical retro-allylation of homoallylic alcohols via the cleavage of the C(sp3)–C(sp3) bond. In this reaction, a variety of sulfonyl hydrazides were employed as the environmentally friendly radical sources via an electrochemical dehydrazination with the release of N2 and H2 as the byproducts, leading to sulfonyl allylic compounds in moderate to