Photochemical transformations of small ring heterocyclic compounds. 91. Photochemistry of the chroman and 3-chromanone ring systems. An example of tautomeric control of excited-state chemistry
Thienobenzynes, which are thiophene-fused novel benzyne species, are efficiently generated via an iodine–magnesium exchange reaction of ortho-iodoaryl triflate-type precursors using a silylmethyl Grignardreagent as the activator. The method allows for facile preparation of a diverse range of multisubstituted benzothiophenes from readily available simple benzothiophenes.
Cycloadditions of isoquinolinium salts: evidence for a two-step mechanism in a stereocontrolled synthesis of substituted tetralins
作者:Ram B. Gupta、Richard W. Franck
DOI:10.1021/ja00252a015
日期:1987.9
Aspects synthetiques et mecanistiques de la reaction du chlorure de (dinitrophenyl-2,4)-2 isoquinoleinium avec des ethers vinyliques
Aspects synthetiques et mecanistiques de la reaction du chlorure de (dinitrophenyl-2,4)-2 isoquinoleinium avec des ethersvinyliques
Inverse electron demand diels-alder reactions of 3-carbomethoxy-2-pyrones. Controlled introduction of oxygenated aromatics: benzene, phenol, catechol, resorcinol, pyrogallol annulation.
作者:Dale L. Boger、Michael D. Mullican
DOI:10.1016/s0040-4039(01)99816-8
日期:1983.1
m-CPBA] allows the preparation of a full range of oxygen substituted aromatics from a single intermediate and represent methods of benzene, 1-, 2- or 3-phenol, symmetrical or unsymmetrical catechol, resorcinol and pyrogallol annulation.
Selective Aryne Formation via Grob Fragmentation from the [2+2] Cycloadducts of 3-Triflyloxyarynes
作者:Jiarong Shi、Hai Xu、Dachuan Qiu、Jia He、Yang Li
DOI:10.1021/jacs.6b12161
日期:2017.1.18
chemoselective ring-opening protocol of the formal [2+2] cycloadducts of 3-triflyloxyarynes was developed to generate 2,3-aryne intermediate via Grob fragmentation. A variety of 1,3-di- and 1,2,3-trisubstituted arenes could be readily accessed through this [2+2] cycloaddition-2,3-aryne formation sequence. The regioselectivity in these transformations originates from the steric repulsion of the aliphatic chain
boronic acids as key steps without using any protectinggroups. The in‐situ‐generated benzynes underwent [4+2], (3+2), and [2+2] cycloadditions to give the benzo‐fused multicyclic compounds while maintaining such functional groups. In particular, 4‐aminobenzyne was generated for the first time and underwent the Diels–Alder reaction with the free primary amino group remaining intact.