phosphine-catalyzed transformation has been developed for the synthesis of chiral cyclobutene triesters and fluorinated spirocyclic compounds. The strategy involved a P(III)/P(V) redox cycling process, via in situ reduction of phosphine oxide with phenylsilane. This catalytic methodology has enabled the enantioselective synthesis of functionalized cyclobutenes (24 examples, up to 94% ee). On the occasion of the
Catalytic and Asymmetric Process via P<sup>III</sup>/P<sup>V</sup>═O Redox Cycling: Access to (Trifluoromethyl)cyclobutenes via a Michael Addition/Wittig Olefination Reaction
In the present study, we report the first enantioselective and highly efficient phosphine-catalyzed process via a chemoselective in situ phosphine oxide reduction. Starting with 4,4,4-trifluorobutane-1,3-dione and dialkyl acetylenedicarboxylate substrates, highly functionalized fluorinated cyclobutenes were obtained in excellent yields and enantioselectivities. Using the same methodology, CF3-spirocyclobutene
Exploiting the Facile Release of Trifluoroacetate for the α-Methylenation of the Sterically Hindered Carbonyl Groups on (+)-Sclareolide and (−)-Eburnamonine
作者:Mark V. Riofski、Jinu P. John、Mary M. Zheng、Julia Kirshner、David A. Colby
DOI:10.1021/jo102114f
日期:2011.5.20
applied this method to produce semisynthetic derivatives of the natural products (+)-sclareolide and (−)-eburnamonine, in which the carbonylgroup is proximal to bulky functional groups. Mechanistic insight is also provided from a time course of 19F NMR. Biological evaluation of the natural-product-derived enones led to the identification of a derivative of (−)-eburnamonine with significant cytotoxicity
报道了一种用于羰基的α-甲基化的有效方法,并且该转化通过在烯烃形成过程中容易地消除三氟乙酸盐来完成。该方法代表了在空间障碍情况下对现有方案的改进,并且我们已经证明了该方法在一系列酮,内酰胺和内酯中的实用性。此外,我们已经应用此方法生产了天然产物(+)-香紫苏内酯和(-)-金枪鱼碱的半合成衍生物,其中羰基基团靠近庞大的官能团。还提供19分钟的时间过程的机械洞察力1 H NMR。对天然产物衍生的烯酮的生物学评估导致鉴定出在耐药MDA-MB-231乳腺癌细胞中具有显着细胞毒性(LC 50 = 14.12μM)的(-)-氨丁胺衍生物。
A Study of Some Fluorine-containing β-Diketones<sup>1</sup>
作者:J. D. Park、H. A. Brown、J. R. Lacher
DOI:10.1021/ja01115a041
日期:1953.10
[3+3] Cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes—a new approach to diverse CF3-substituted fluorenes, dibenzofurans, 9,10-dihydrophenanthrenes and 6H-benzo[c]chromenes
作者:Stefan Büttner、Nazken K. Kelzhanova、Zharylkasyn A. Abilov、Alexander Villinger、Peter Langer
DOI:10.1016/j.tet.2012.01.101
日期:2012.5
Trifluoromethyl-substituted fluorenes, dibenzofurans, 9,10-dihydrophenanthrenes and 6H-benzo[c] chromenes were prepared by formal [3+3] cyclizations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes. The reactions proceeded with very good regioselectivity. The product distribution depends on the type of 1,3-dielectrophile employed and can be explained by electronic reasons. (C) 2012 Elsevier Ltd. All rights reserved.