Intramolecular reactions of 2-propynylsilanes with n-acyliminium ions
作者:Wim J. Klaver、Marinus J. Moolenaar、Henk Hiemstra、W.Nico Speckamp
DOI:10.1016/s0040-4020(01)86638-2
日期:1988.1
precursors lead to bridged azabicyclic systems 34–45 (Table I), containing the uncommon α-allenic amide functionality. After introduction of a tert-butoxycarbonyl or a tosyl group onto the lactam nitrogen atom, these molecules react with cuprates in an SN2' fashion. The products 52–58 (Table II) are angularly functionalized trans-fused carbobicycles containing a 1,3-diene moiety.
2-丙炔基硅烷与环状N-酰基亚胺离子前体的分子内酸辅助反应会导致桥连的氮杂双环体系34 – 45(表I),其中含有罕见的α-烯丙基酰胺官能团。在内酰胺氮原子上引入叔丁氧基羰基或甲苯磺酰基后,这些分子以S N 2'的方式与铜酸盐反应。产物52 – 58(表II)是含有1,3-二烯部分的有角度官能化的反式融合碳环。
Photo-Fries-type rearrangement of cyclic enamides. An efficient route to structurally diverse five-membered enaminones
作者:Piotr Szcześniak、Bartłomiej Furman
DOI:10.1039/d1cc06297b
日期:——
A simple, efficient and user-friendly protocol for the preparation of structurally diverse enaminones from enamides has been developed. The strategy is based on a photo-induced intramolecular Fries-type rearrangement. The photochemicaltransformation proceeds under mild reaction conditions, applies to a broad substrate range, is highly economic, and limits the amount of waste produced. The proposed
Oxazaborolidine catalysed enantioselective reduction of cyclic meso-imides
作者:Martin Ostendorf、Romeo Romagnoli、Isabel Cabeza Pereiro、Eric C. Roos、Marinus J. Moolenaar、W.Nico Speckamp、Henk Hiemstra
DOI:10.1016/s0957-4166(97)00154-7
日期:1997.6
Full details of the enantioselective reduction of cyclic meso-imides catalysed by an enantiopure oxazaborolidine derived from (S)-alpha,alpha-diphenylprolinol are reported. Treatment of the imides with borane in the presence of the catalyst led to a mixture of cis- and trans-hydroxylactams and, after subsequent ethanolysis, to the corresponding diastereomerically pure trans-ethoxylactams. The enantiomeric excesses were shown to be 68-94% by HPLC-determination. One example, in which the ethoxylactam was converted into the benzenesulfonyllactam, could be crystallized to >99% enantiomeric purity. (C) 1997 Elsevier Science Ltd.
CROCKETT G. C.; SWANSON B. J.; ANDERSON D. R.; KOCH T. H., SYNTH. COMMUN., 1981, 11, NO 6, 447-454
作者:CROCKETT G. C.、 SWANSON B. J.、 ANDERSON D. R.、 KOCH T. H.