Umpolung of the reactivity of allylsilanes. Palladium(II) catalyzed cyclization of allylsilyl alcohols: a new route to substituted 2-vinyltetrahydrofurans
摘要:
Functionalized allylsilanes 1-4 undergo palladium(II) catalyzed ring closure to afford 4- and/or 5-substituted 2-vinyltetrahydrofurans (5-8) under mild conditions. The catalytic reactions proceed through (eta(3)-allyl)palladium intermediates formed by palladadesilylation of the allylsilane substrates. (C) 2000 Elsevier Science Ltd. All rights reserved.
Synthesis of stereodefined vinyl-tetrahydropyran and vinyl-octahydrochromene derivatives via acetalization–cyclization of allylsilanes with aldehydes. Origin of the high stereoselectivity
作者:Johan Kjellgren、Kálmán J. Szabó
DOI:10.1016/s0040-4039(01)02340-1
日期:2002.2
Functionalized allylsilanes 1-5 and aldehydes 6-8 undergo Lewis-acid mediated ring closure to afford 2,3,5- or 6-substituted tetrahydropyrans (8 15) and 2,3-substituted octahydrochromenes (16a-b) with excellent stereoselectivity. According to DFT calculations the high stereoselectivity arises from electronically induced steric effects occurring in the key-intermediate of the cyclization. (C) 2002 Elsevier Science Ltd. All rights reserved.
Palladium-Catalyzed Cyclization of Allylsilanes with Nucleophilic Displacement of the Silyl Group
Allylsilanes containing hydroxy or tosylamide groups undergo palladium(II)catalyzed cyclization to afford derivatives of tetrahydrofuran, piperidine, and pyrrolidine. This catalytic reaction proceeds through an (eta3-allyl)palladium intermediate that is generated by allylic displacement of the silyl group of the allylsilane precursors. The internal nucleophilic attack on the (eta3-allyl)palladium intermediates
Umpolung of the reactivity of allylsilanes. Palladium(II) catalyzed cyclization of allylsilyl alcohols: a new route to substituted 2-vinyltetrahydrofurans
作者:István Macsári、Kálmán J. Szabó
DOI:10.1016/s0040-4039(99)02245-5
日期:2000.2
Functionalized allylsilanes 1-4 undergo palladium(II) catalyzed ring closure to afford 4- and/or 5-substituted 2-vinyltetrahydrofurans (5-8) under mild conditions. The catalytic reactions proceed through (eta(3)-allyl)palladium intermediates formed by palladadesilylation of the allylsilane substrates. (C) 2000 Elsevier Science Ltd. All rights reserved.