A Lewis acid-catalyzed tandem reaction enabling 2-arylglycerol derivative as a versatile 1,3-biselectrophile for the synthesis of 4H-chromenes and 2-pyridinones

Acid-catalyzed tandem reactions were established by employing a novel class of 2-arylglycerol derivative,5-aryl-1,3-dioxan-5-ol,as versatile 1,3-biselectrophile.In the reactions,5-aryl-1,3-dioxan-5-ol works like atropaldehydes or 2-aryl malondialdehydes,and can react with 2-naphthols andβ-keto amides,allowing the synthesis of 4H-chromenes and 5-aryl-2-pyridinones.High yields,good functional group tolerance,broad substrate scope and simple reaction operation make this protocol attractive.

Lewis acid-catalyzed[4+2]cycloaddition of 3-alkyl-2-vinylindoles withβ,γ-unsaturatedα-ketoesters

A Lewis acid-catalyzed[4+2]cycloaddition of 3-alkyl-2-vinylindoles withβ,γ-unsaturatedα-ketoesters has been established in the presence of Sc(OTf)3,which afforded a series of indole-containing pyran derivatives in generally good yields(up to 90%yield)with excellent diastereoselectivities(up to >95:5 dr)under mild conditions.This approach not only enriches the chemistry of 3-alkyl-2-vinylindoles,but also has provided an atom-economic method for the synthesis of indole-containing pyran derivatives with potential bioactivity.

Asymmetric Electrochemical Arylation in the Formal Synthesis of(+)-Amurensinine

Asymmetric electrochemical synthesis has emerged as an attractive and sustainable alternative for the distinctive activation of bond connections in the preparation of diverse enantiomerically enriched targets,including natural products and pharmaceutical agents.Herein,we describe the chiral Lewis acid-catalyzed enantioselective electrochemical anodic coupling reaction as a key step in the presented formal synthesis of isopavine alkaloids.

Multiphase surfactant-assisted reaction-separation system in a microchannel reactor

The Lewis acid-catalyzed addition of tri-methylsilyl cyanide to p-chlorobenzaldehyde in a micro-channel reactor was investigated.The microchannel was integrated to promote both reaction and separation of the biphase system.FeF3 and Cu(triflate)2 were used as water-stable Lewis acid catalysts.Sodium dodecyl sulfate was incorporated in the organic-aqueous system to enhance the reactivity and to manipulate the multiphaseflow inside the microchannel.It was found that the dynamics and the kinetics of the multiphase reaction were affected by the new micellar system.Parallel multiphaseflow inside the microchannel was obtained,allowing for continuous and acceptable phase separation.Enhanced selectivity was achieved by operating at lower conversion values.