A General Catalytic Route to Isoindolinones and Tetrahydroisoquinolines: Application in the Synthesis of (±)-Crispine A
作者:Sivasankaran Dhanasekaran、Vishnumaya Bisai、Rajshekhar A. Unhale、Arun Suneja、Vinod K. Singh
DOI:10.1021/ol502842f
日期:2014.12.5
An unprecedented highly efficient Lewis acid catalyzed one-pot cascade has been demonstrated as a general catalytic system for the synthesis of diversely substituted isoindolinones and tetrahydroisoquinolines. The cascade effects one C–C and two C–N bond-forming events in one pot. Several interesting transformations of the products into valuable synthetic intermediates are featured with the successful
Conjugate Addition−Dipolar Cycloaddition Cascade for the Synthesis of Benzo[<i>a</i>]quinolizine and Indolo[<i>a</i>]quinolizine Scaffolds: Application to the Total Synthesis of (±)-Yohimbenone
作者:Chad J. Stearman、Michael Wilson、Albert Padwa
DOI:10.1021/jo9003579
日期:2009.5.1
A highly efficient total synthesis of (±)-yohimbenone and a formal synthesis of (±)-emetine is described. The key element of the synthesis consists of a conjugate addition−dipolar cycloaddition of 2,3-bis(phenylsulfonyl)-1,3-butadiene with an appropriate oxime. The resulting cycloadducts are cleaved reductively to provide azapolycyclic scaffolds with strategically placed functionality for further manipulation
A novel approach to functionalisedanalogues of Cephalotaxine is described; the fused azaspirocyclic skeleton (11) has been constructed stereospecifically in nine steps (overall yield 15%) starting from 3,4-dimethoxy-carbomethoxymethyl-benzene.
Asymmetric Alkynylation/Lactamization Cascade: An Expeditious Entry to Enantiomerically Enriched Isoindolinones
作者:Vishnumaya Bisai、Arun Suneja、Vinod K. Singh
DOI:10.1002/anie.201405074
日期:2014.9.26
An unprecedented CuI–pybox‐diPh‐catalyzed highly enantioselective (up to >99 % ee) alkynylation/lactamizationcascade has been developed as a general catalytic system for the synthesis of diversely substituted isoindolinones of immense biological importance. The cascade effects one CC and two CN bond‐forming events in one reaction vessel under operationally simple, additive‐free reaction conditions
前所未有的Cu I – pybox-diPh催化的高对映选择性(高达ee高达99%以上 )的炔基化/内酰胺化级联反应已被开发为合成具有广泛生物学重要性的异取代异吲哚啉酮的通用催化体系。在操作简单,无添加剂的条件下,级联反应可在一个反应容器中实现一个CC和两个CN键形成事件,并具有良好的收率。该方法被进一步扩展为以两步顺序合成具有多种生物活性天然产物的四氢异喹啉骨架,具有显着的选择性(最高94% ee)。
A General Methodology for the Enantioselective Synthesis of 1-Substituted Tetrahydroisoquinoline Alkaloids
is easily accessible by cyclocondensation of δ-oxoester 1 with (R)-phenylglycinol, a three-step synthetic route to enantiopure 1-substitutedtetrahydroisoquinolines, including 1-alkyl-, 1-aryl-, and 1-benzyltetrahydroisoquinoline alkaloids, as well as the tricyclic alkaloid (–)-crispine A, has been developed. The key step is a stereoselective α-amidoalkylation reaction using the appropriate Grignard