Multiple approaches to enantiopure spirocyclic benzofuranones using organocatalytic cascade reactions
作者:Carlo Cassani、Xu Tian、Eduardo C. Escudero-Adán、Paolo Melchiorre
DOI:10.1039/c0cc01957g
日期:——
Three distinct aminocatalytic cascadereactions leading to enantiomerically pure spirocyclic benzofuranones have been devised, highlighting the ability of organocascade to generate high degrees of stereochemical and architectural complexity in a single chemical transformation.
Phosphine-containing Lewis base catalyzed cyclization of benzofuranone type electron-deficient alkenes with allenoates: a facile synthesis of spirocyclic benzofuranones
作者:Xin Li、Feng Wang、Nan Dong、Jin-Pei Cheng
DOI:10.1039/c3ob27288e
日期:——
A regioselective [3 + 2] cycloaddition of benzofuranone type active olefins with allenoates catalyzed by trivalent phosphines has been developed, which provided an easy access to enriched functionalized spirocyclic benzofuranones. The reactions accommodated a number of benzofuranone type electron-deficient olefins and allenoates to give the desired 3-spirocyclopentane benzofuran-2-ones or 2-spirocyclopentane benzofuran-3-ones with moderate to excellent yields (up to 99%) and moderate to good regioselectivities (up to 11 : 1).
Divergent Metal-Free [4 + 2] Cascade Reaction of 1-Indanylidenemalononitrile with 3-Benzylidenebenzofuran-2(3<i>H</i>)-one: Access to Spiro-dihydrofluorene-benzofuranone and Axially Chiral Fluorenylamine-phenol Derivatives
conditions, and various spiro-dihydrofluorene-benzofuranones were produced in gratifying results, respectively. It is worthnoting that both the spiro and axially chiral products can be obtained by tuning the reaction conditions. The mechanism of the transformation was also studied by quantum chemical calculations.
在温和的反应条件下,在温和的反应条件下,开发了 1-茚满基丙二腈与 3-亚苄基苯并呋喃-2(3 H )-one的高效级联反应,并分别产生了各种螺-二氢芴-苯并呋喃酮。值得注意的是,螺旋和轴向手性产物都可以通过调整反应条件来获得。还通过量子化学计算研究了转变的机制。
Diastereoselective synthesis of chroman bearing spirobenzofuranone scaffolds <i>via</i> oxa-Michael/1,6-conjugated addition of <i>para</i>-quinone methides with benzofuranone-type olefins
作者:Hongmei Qin、Qimei Xie、Long He
DOI:10.1039/d2ra03031d
日期:——
A simple and convenient cyclization of ortho-hydroxyphenyl-substituted para-quinone methides with benzofuran-2-one type active olefins via oxa-Michael/1,6-conjugated addition has been developed, which afforded an easy access to enriched functionalized chroman-spirobenzofuran-2-one scaffolds with good to excellent yields (up to 90%) and diastereoselectivities (up to >19 : 1 dr). This reaction provided