Synthesis of Vitamin K and Related Naphthoquinones via Demethoxycarbonylative Annulations and a Retro-Wittig Rearrangement
作者:Dipakranjan Mal、Ketaki Ghosh、Supriti Jana
DOI:10.1021/acs.orglett.5b02920
日期:2015.12.4
Anionic annulations of 3-nucleofugal phthalides with α-alkyl(aryl)acrylates involving a demethoxycarbonylation provide a succinct synthesis of vitamin K and related naphthoquinones. Also reported is a new cascade reaction stemming from a Cope–retro-Wittig rearrangement. This cascade leads to direct formation of 1-hydroxy-4-prenyloxynaphthalene-2-carboxylates from the corresponding α-prenyl acrylate
Asymmetric Synthesis of Functionalized Dihydronaphthoquinones Containing Quaternary Carbon Centers via a Metal-Free Catalytic Intramolecular Acylcyanation of Activated Alkenes
作者:Zhe Zhuang、Zhi-Peng Hu、Wei-Wei Liao
DOI:10.1021/ol501427h
日期:2014.6.20
metal-free catalytic annulation was developed through a Lewis base-catalyzed asymmetric allylic alkylation and the ensuing unprecedented asymmetric intramolecular acylcyanation of alkenes. This protocol provides a unique and facile access to prepare enantioenriched densely functionalized dihydronaphthoquinones accompanied by enantiomerically pure 3,3-disubstituted phthalides bearing quaternarycarbon centers
Anionic Annulation of 3-Cyanophthalides with Allene Carboxylates: A Carbon-Conserved Synthesis of Naphtho[<i>b</i>]furanones
作者:Supriti Jana、Dipakranjan Mal
DOI:10.1021/acs.joc.8b00272
日期:2018.4.20
The reaction of 3-cyanophthalides with allene carboxylates in the presence of tBuOLi results in a tandem annulation furnishing naphtho[b]furanones in good yields with no loss of carbon. The carbon economy is explained by a tandem process, in which the initially expelled cyanide induces the second annulation.
在t BuOLi的存在下3-氰基邻苯二甲酸酯与羧酸烯丙酯的反应导致串联环化提供了萘[ b ]呋喃酮,收率很好,并且没有碳的损失。碳经济通过串联过程来解释,其中最初排出的氰化物引起第二次成环。
4-Bromopyrenes with Arylacetonitriles and 3-Cyanophthalides Under Aryne-Forming Conditions
作者:Wei Han、Joe Tran、Hongming Zhang、Stacey Jeffrey、Dan Swartling、George P. Ford、Ed Biehl
DOI:10.1055/s-1995-4016
日期:1995.7
4-Bromopyrene reacts with arylacetonitriles under LDA-mediated aryne-forming conditions to yield rearranged 5-arylmethyl-4-pyrenecarbonitriles through 4-pyryne; no simple addition products were observed. These product ratios are in accord with predictions based on the stabilities of the respective 4-pyryne (-5.55 kcal/mol) intermediates relative to benzyne, determined by AM1 molecular orbital calculations. In addition, 4-pyryne was annulated by 3-lithiated 3-cyanophthalides to dibenzo[de,qr]naphthacene-9,14-diones which were subsequently reductively dimethylated to 9,14-dimethoxydibenzo[de,qr]naphthacenes in overall good yields.
Angucycline C5 Glycosides: Regio- and Stereocontrolled Synthesis and Cytotoxicity
作者:Prithiba Mitra、Birendra Behera、Tapas K. Maiti、Dipakranjan Mal
DOI:10.1021/jo4013892
日期:2013.10.4
This study discloses a general and convergent route for the regio- and stereospecific construction of the C5 glycosyl angucycline framework of mayamycin. C-Glycosidation, dearomatization, and Hauser annulation are the key steps. The synthetic analogues show cytotoxicity against different human cancer cell lines with IC50 values between 16.4 and 1.2 μM.