Preparation of Macrocyclic <i>Z</i>-Enoates and (<i>E</i>,<i>Z</i>)- or (<i>Z</i>,<i>E</i>)-Dienoates through Catalytic Stereoselective Ring-Closing Metathesis
作者:Hanmo Zhang、Elsie C. Yu、Sebastian Torker、Richard R. Schrock、Amir H. Hoveyda
DOI:10.1021/ja510768c
日期:2014.11.26
stereoselective macrocyclic ring-closing metathesis reactions that generate Z-enoates as well as (E,Z)- or (Z,E)-dienoates are disclosed. Reactions promoted by 3.0–10 mol % of a Mo-based monoaryloxide pyrrolide complex proceed to completion within 2–6 h at room temperature. The desired macrocycles are formed in 79:21 to >98:2 Z/E selectivity; stereoisomerically pure products can be obtained in 43–75% yield after
Kumulierte Ylide XX.<sup>1</sup>Synthesen (<i>E</i>)-α,β-ungesättigter macrocyclischer Lactone durch intramolekulare Wittig-Olefinierung via Triphenylphosphoranylidenketen<sup>2</sup>
作者:Hans Jürgen Bestmann、Rainer Schobert
DOI:10.1055/s-1989-27271
日期:——
Cumulated Ylides XX.1 Syntheses of (E)-α,β-Unsaturated Macrocyclic Lactones by Intramolecular Wittig-Olefination via Triphenylphosphoranylideneketene2 Two methods for closure of macrocyclic lactone rings by intramolecular Wittig reaction of (Ï-oxoalkoxy)carbonylmethylenetriphenylphosphoranes are described. The latter are easily accessible by addition of the appropriate (free or protected) Ï-hydroxyalkanals to the cumulated ylide triphenylphosphoranylideneketene. Examples are then given for the use of these methods in natural product synthesis.
Conversion of lactones to the higher homologous α, β-unsaturated lactones v/a hypervalent iodine oxidation of 1-trimethylsilyloxy-2-oxa[n.1.0] cycloalkanes
Bestmann, Hans Juergen; Schobert, Rainer, Angewandte Chemie, 1985, vol. 97, # 9, p. 783 - 784
作者:Bestmann, Hans Juergen、Schobert, Rainer
DOI:——
日期:——
An improved and novel approach to macrolactonisation using di-tert-butyl dicarbonate
作者:M. Nagarajan、V.Satish Kumar、B.Venkateswara Rao
DOI:10.1016/s0040-4020(99)00718-8
日期:1999.10
A new, facile, mild and simple method for the synthesis of macrolides was achieved from omega- hydroxy acids using di-tert-butyl dicarbonate ( Boc(2)O), a cheap and commercially available reagent. A wide range of substrates were tested and give good yield of lactones. The effect of various simple bases on the yield of the macrolactonisation reaction was also studied. (C) 1999 Published by Elsevier Science Ltd. All rights reserved.