Product selectivity control based on a liquidâliquid parallel laminar flow has been successfully demonstrated by using a microreactor. Our electrochemical microreactor system enables regioselective cross-coupling reaction of aldehyde with allylic chloridevia chemoselective cathodic reduction of substrate by the combined use of suitable flow mode and corresponding cathode material. The formation of liquidâliquid parallel laminar flow in the microreactor was supported by the estimation of benzaldehyde diffusion coefficient and computational fluid dynamics simulation. The diffusion coefficient for benzaldehyde in Bu4NClO4-HMPA medium was determined to be 1.32 Ã 10â7 cm2sâ1 by electrochemical measurements, and the flow simulation using this value revealed the formation of clear concentration gradient of benzaldehyde in the microreactor channel over a specific channel length. In addition, the necessity of the liquidâliquid parallel laminar flow was confirmed by flow mode experiments.
A new strategy for chemoselective reaction using a two inlet micro-flow reactor is described. In this system, the combined use of suitable flow mode and corresponding cathode material enables chemoselective cathodic reduction to control the product regioselectivity in carbonyl allylation.
In Situ Formation of Allyl Ketones via Hiyama−Nozaki Reactions Followed by a Chromium-Mediated Oppenauer Oxidation
作者:Henri S. Schrekker、Martin W. G. de Bolster、Romano V. A. Orru、Ludger A. Wessjohann
DOI:10.1021/jo001750u
日期:2002.4.1
dependent on the substitution pattern of the reaction partners and the reaction conditions. An appropriate choice of these can lead to preferential formation of ketones instead of the alcohols. In addition to its synthetic usefulness, the oxidation-reduction equilibrium is of the utmost importance for the design of enantioselective Hiyama-Nozaki reactions because it is also a potential racemization pathway
Iminoxyl Radical-Promoted Oxycyanation and Aminocyanation of Unactivated Alkenes: Synthesis of Cyano-Featured Isoxazolines and Cyclic Nitrones
作者:Fei Chen、Fei-Fei Zhu、Man Zhang、Rui-Hua Liu、Wei Yu、Bing Han
DOI:10.1021/acs.orglett.7b00826
日期:2017.6.16
oxidant, CuCN as the commercially available cyanating reagent, and pentamethyldiethylenetriamine (PMDETA) as the ligand. By using this protocol, a series of useful cyano-featured isoxazolines and cyclicnitrones were efficiently prepared.
modification in syntheticchemistry but it remains a formidable challenge to perform on unstrained skeletons. Herein, we describe a radical addition-enabled C–C σ-bond cleavage/reconstruction reaction of unstrained allyl ketones to access various functional indanones bearing a benzylic quaternary center. The synthetic utility of this method has been showcased by the first total synthesis of carexane L, an indanone-based
C-C σ 键断裂和重建是合成化学中结构修饰的重要工具,但在无应变骨架上进行仍然是一个巨大的挑战。在此,我们描述了无张力烯丙基酮的自由基加成C-C σ-键裂解/重建反应,以获得带有苄基四元中心的各种功能性茚满酮。该方法的合成实用性已通过茚满酮天然产物 Carexane L 的首次全合成得到展示。