Polymer-supported tertiaryphosphine (JJ–TPP) as a green and recyclable organocatalyst for α-addition of carbon nucleophiles to α,β-unsaturated compounds
摘要:
JJ - TPP has been demonstrated as an effective and reusable organocatalyst for alpha-addition of carbon nucleophiles to alpha,beta-unsaturated compounds under very mild and environmentally friendly conditions. Under the optimized reaction conditions, the desired addition products were obtained as only E isomer with 18 - 90% isolated yields. (c) 2007 Elsevier Ltd. All rights reserved.
Privilege Ynone Synthesis via Palladium-Catalyzed Alkynylation of “Super-Active Esters”
摘要:
A neat palladium-catalyzed alkynylation reaction was developed with "super-active ester" as the carbonyl electrophile, which provides a dean-and efficient synthetic protocol for a broad array Of ynone compounds under CO-, Cu-,, ligand-, and base-free conditions. The superior activity of triazine ester was rationalized by the strong electron;withdrawing ability and the unique affinity of triazine On palladium. A mechanistic experiment clearly demonstrated that the N-Pd coordination of triazine plays a crucial role for the highly efficient C-O activation.
Dual Hypervalent Iodine(III) Reagents and Photoredox Catalysis Enable Decarboxylative Ynonylation under Mild Conditions
作者:Hanchu Huang、Guojin Zhang、Yiyun Chen
DOI:10.1002/anie.201502369
日期:2015.6.26
combination of hypervalentiodine(III) reagents (HIR) and photoredoxcatalysis with visible light has enabled chemoselective decarboxylativeynonylation to construct ynones, ynamides, and ynoates. This ynonylation occurs effectively undermild reaction conditions at room temperature and on substrates with various sensitive and reactive functional groups. The reaction represents the first HIR/photoredox dual
Regio- and Stereoselective Hydrosulfonylation of Electron-Deficient Alkynes: Access to Both E- and Z-β-Sulfonyl-α,β-Unsaturated Carbonyl Compounds
作者:Wei Zhang、Gabriel M. Johnson、Zhi Guan、Yan-Hong He
DOI:10.1002/adsc.201801032
日期:2018.12.3
sulfinic acids to access both E‐ and Z‐β‐sulfonyl‐α,β‐unsaturated carbonyl compounds has been developed. We propose that this reaction via a hydroxylallene intermediate delivers the thermodynamically stable E isomer, or via a concerted termolecular AdE3 mechanism affords Z isomer. The stereoselectivity of addition (syn or anti) can be controlled by varying the sulfonyl sources and acidic buffer solutions
已经开发出一种电子不足的炔烃,通过亚磺酸钠或亚磺酸进行无金属的氢磺酰化反应,以同时获得E-和Z - β-磺酰基-α,β-不饱和羰基化合物。我们建议该反应通过羟基丙二烯中间体传递热力学稳定的E异构体,或通过一致的分子Ad E 3机理提供Z异构体。加成的立体选择性(合成或反合成)可以通过改变磺酰基来源和酸性缓冲溶液来控制。该协议展示了内部或末端炔烃的广泛底物范围,包括各种取代的炔酮和炔基酯。这种方法温和,高效,操作简单且易于扩展。
Zinc‐Catalyzed Dehydrogenative Cross‐Coupling of Terminal Alkynes with Aldehydes: Access to Ynones
作者:Shan Tang、Li Zeng、Yichang Liu、Aiwen Lei
DOI:10.1002/anie.201509042
日期:2015.12.21
Because of the lack of redox ability, zinc has seldom been used as a catalyst in dehydrogenativecross‐coupling reactions. Herein, a novel zinc‐catalyzeddehydrogenativeC(sp2)H/C(sp)H cross‐coupling of terminal alkynes with aldehydes was developed, and provides a simple way to access ynones from readily available materials under mild reaction conditions. Good reaction selectivity can be achieved
C(CO)–C(Ar) bond cleavage of β-enaminones has been realized under mild and transition-metal-free conditions. The cascade transformation based on this C–C bond cleavage involves 1,3-O/C migration and aerobic hydroxylation and leads to various 5-hydroxy-1H-pyrrol-2(5H)-ones with broad functional group tolerance. The application of this methodology has been showcased by preparing 5-alkoxy-1H-pyrrol-2(5H)-one
在温和且无过渡金属的条件下,实现了前所未有的β-烯胺酮的C(CO)-C(Ar)键裂解。基于这种C–C键断裂的级联转化涉及1,3-O / C迁移和需氧羟基化,并导致各种具有广泛官能团耐受性的5-羟基-1 H-吡咯-2(5 H)-酮。通过制备5-烷氧基-1 H-吡咯-2(5 H)-one衍生物和吡咯并[ 2,1- a ]异喹啉-3-酮衍生物展示了该方法的应用。