A One-Step Synthesis of a Poly(iptycene) through an Unusual Diels−Alder Cyclization/Dechlorination of Tetrachloropentacene
摘要:
We have discovered the first reaction of a substituted pentacene molecule as a dienophile. A surprisingly clean Diels-Alder self-coupling of Cl4Pn leads to a novel ladder polymer, poly(iptycene), which can be converted to a conducting carbon at relatively low temperature (600-900 degrees C). Theoretical calculations of the former reaction suggest a biradical asymmetric mechanism, despite highly symmetric reactants.
Functionalization of Acetalic C(sp3)-H Bonds by Scandium(III) Triflate-Catalyzed Intramolecular Redox Reactions: Tandem 1,4-Hydride Transfer/1,5-Cyclization Processes Leading to Protected 1-Indanones
作者:Mateo Alajarin、Marta Marin-Luna、Angel Vidal
DOI:10.1002/adsc.201000812
日期:2011.3.7
A new CC bond forming reactionleading to adjacent quaternary carbons is reported. It is a one‐pot hydride shift/cyclization process facilitated by the hydricity of the acetalicCH bonds, with benzylidenemalonate fragments as electrophilic hydride acceptors, and the catalysis of scandium(III) triflate. The reaction products are 1,2‐dihydroindane derivatives. Alkoxy and alkanethiolate groups can be
Starting from aromaticortho-dialdehydes, we devised a homo-elongation protocol that combines a Wittig olefination and subsequent intramolecular Knoevenagel condensation to produce acene diesters and dinitriles.
For the preparation of 3-alkoxyphthalides from phthalaldehydes and alcohols, a cyclization reaction in the presence of a rhodium(III) catalyst and copper(II) salt is reported. Cyclization of phthalaldehydes also occurs with 1,3-dicarbonyl compounds under similar conditions to produce 3-substituted phthalides in good yields. An acylrhodium(III) species might be a key intermediate in these cyclization
Enantioselective Iridium-Catalyzed Phthalide Formation through Internal Redox Allylation of Phthalaldehydes
作者:James M. Cabrera、Johannes Tauber、Michael J. Krische
DOI:10.1002/anie.201712015
日期:2018.1.26
An inside job: Enantioselective phthalide synthesis was achieved through internal redox allylation of o‐phthalaldehydes. Oxidative esterification is balanced by reductive carbonyl addition to achieve an overall redox‐neutral process. This method enabled formal syntheses of ent‐spirolaxine methyl ether and CJ‐12,954.
Silver-Catalyzed Formal Inverse Electron-Demand Diels–Alder Reaction of 1,2-Diazines and Siloxy Alkynes
作者:Yunus E. Türkmen、Timothy J. Montavon、Sergey A. Kozmin、Viresh H. Rawal
DOI:10.1021/ja302537j
日期:2012.6.6
A highly effective silver-catalyzed formal inverse electron-demand Diels-Alder reaction of 1,2-diazines and siloxyalkynes has been developed. The reactions provide ready access to a wide range of siloxy naphthalenes and anthracenes, which are formed in good to high yields, under mild reaction conditions, using low catalyst loadings.