Regioselective Single-Electron Tsuji–Trost Reaction of Allylic Alcohols: A Photoredox/Nickel Dual Catalytic Approach
作者:Zheng-Jun Wang、Shuai Zheng、Eugénie Romero、Jennifer K. Matsui、Gary A. Molander
DOI:10.1021/acs.orglett.9b02473
日期:2019.8.16
A radical-mediated functionalization of allyl alcohol derived partners with a variety of alkyl 1,4-dihydropyridines via photoredox/nickel dual catalysis is described. This transformation transpires with high linear and E-selectivity, avoiding the requirement of harsh conditions (e.g., strong base, elevated temperature). Additionally, using aryl sulfinate salts as radical precursors, allyl sulfones
Copper-catalyzed oxidative decarboxylative alkylation of cinnamic acids with 4-alkyl-1,4-dihydropyridines
作者:Dong Zhang、Zi-Liang Tang、Xuan-Hui Ouyang、Ren-Jie Song、Jin-Heng Li
DOI:10.1039/d0cc06401g
日期:——
We have developed a new oxidative decarboxylation of cinnamic acids with 4-alkyl-1,4-dihydropyridines to construct C(sp3)-C(sp2) bond in the presence of copper catalyst and dicumyl peroxide (DCP). A variety of internal alkenes have been obtained with mild condition, broad substrates scope and excellent functional groups tolerance. This method has significant potential for application by using inexpensive
The direct introduction of sp3 carbon fragments at the β position of α,β-unsaturated aldehydes is greatly complicated by competing 1,2-addition manifolds. Previous catalytic enantioselective conjugate addition methods, based on the use of organometallic reagents or ground-state iminium ion activation, could not provide general and efficient solutions. We report herein that, by turning them into strong
α-ketoacids enabled by the Lewis acid activation. The in situ boron complex formation is confirmed by various spectroscopic measurements and mechanistic probing experiments, which facilitates various alkyl boronic acid addition to the carbonyl group and prevents the cleavage of the newly-formed C-C bond. Diversely substituted lactates can be synthesized from readily available alkyl boronic acids and ketoacids
由于所得烷氧基自由基容易断裂,分子间自由基加成到羰基上是困难的。迄今为止,酮的分子间自由基加成是构建季碳中心的一种有价值的方法,仍然是一项艰巨的合成挑战。在这里,我们报告了第一个可见光诱导的分子间烷基硼酸加成到 α-酮酸通过路易斯酸活化实现的。各种光谱测量和机械探测实验证实了原位硼配合物的形成,这有助于将各种烷基硼酸加成到羰基上,并防止新形成的 CC 键断裂。在室温下,仅在可见光照射下,无需任何额外试剂,即可由易得的烷基硼酸和酮酸合成不同取代的乳酸酯。这种硼活化方法可以扩展到作为自由基前体的烷基二氢吡啶与用于伯、仲和叔烷基自由基加成的外部硼试剂。在流动反应器中的无金属条件下,药学上有用的抗胆碱能前体很容易放大到数克。