Silver nitrate‐catalyzed cascade decarboxylation and oxidativecyclization of α‐oxocarboxylic acids, alkenes, and aldehydes is demonstrated for the first time. With ammonium persulfate as the oxidant, the cascade reactions afford dihydroflavonoid derivatives as products in moderate to good yields, exhibiting a broad substrate tolerance. Control experiments indicated that the mechanism includes a radical
Urea/Transition-Metal Cooperative Catalyst for anti-Selective Asymmetric Nitroaldol Reactions
作者:Kai Lang、Jongwoo Park、Sukwon Hong
DOI:10.1002/anie.201107785
日期:2012.2.13
A cooperativecatalyst that features urea H‐bonding and a cobalt center was developed for anti‐selective asymmetric Henry reactions (see scheme). The H‐bonds of urea play a crucial role in the improvement in yield (from 30 % to 84 %), enantioselectivity (from 78 % to 96 %), and anti diastereoselectivity (from 3:1 to 48:1). A short synthesis of (1R,2S)‐methoxamine hydrochloride was also accomplished
Organophotoredox‐Catalyzed Cascade Radical Annulation of 2‐(Allyloxy)arylaldehydes with
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‐(acyloxy)phthalimides: Towards Alkylated Chroman‐4‐one Derivatives
作者:Sanju Das、Sushanta Kumar Parida、Tanumoy Mandal、Laxmikanta Sing、Suman De Sarkar、Sandip Murarka
DOI:10.1002/asia.201901735
日期:2020.3.2
approach for the synthesis of highly important 3-alkyl substituted chroman-4-one scaffold is developed using visible light induced radicalcascade cyclization strategy. The reaction is initiated through the generation of alkyl radicals from N-(acyloxy)phthalimides under photoredox conditions, which subsequently undergo intermolecular cascaderadical cyclization on 2-(allyloxy)arylaldehydes to afford chroman-4-one
A general and metal-free visible-light-induced decarboxylative arylation procedure at room temperature was described for the construction of acylated heterocyclic derivatives, such as benzimidazo/indolo[2,1-a]isoquinolin-6(5H)-ones, aroylazaspiro[4.5]trienones, thioflavones, and so on. This practical arylation procedure was conducted by using 2,4,5,6-tetra(9H-carbazol-9-yl)isophthalonitrile (4CzIPN)
描述了一种在室温下通用且无金属的可见光诱导的脱羧芳基化方法,用于构建酰化杂环衍生物,例如苯并咪唑/吲哚并[ 2,1 - a ]异喹啉-6(5 H)-ones,芳酰基azaspiro [4.5]三烯酮,硫代黄酮等。通过在温和的条件下使用2,4,5,6-四(9 H-咔唑-9-基)间苯二甲腈(4CzIPN)作为光催化剂来进行该实用的芳基化步骤,避免了使用额外的碱,传统的加热,和金属试剂。
One-Pot Synthesis of 5-Amino-2,5-dihydro-1-benzoxepines: Access to Pharmacologically Active Heterocyclic Scaffolds
作者:Ewen D. D. Calder、Salaheddin A. I. Sharif、Fiona I. McGonagle、Andrew Sutherland
DOI:10.1021/acs.joc.5b00583
日期:2015.5.1
A one-pot multibond-forming process involving a thermally mediated Overman rearrangement and a ring closing metathesis reaction of allylic trichloroacetimidates bearing a 2-allyloxyaryl group has been developed for the synthesis of 5-amino-substituted 2,5-dihydro-1-benzoxepines. Chemoselective reduction and functionalization of these compounds allowed access to a range of pharmacologically active 5-amino-2