(+/-)-Terpestacin has been synthesized through C-alkylation of beta-keto lactone 9 with chain portion 12. These two compounds were derived from 2-cyclopenten-1-ylactic acid and E,E-farnesol, respectively. (C) 1997 Elsevier Science Ltd. All rights reserved.
decomposition of the methanesulfonyl radical into the methyl radical and the subsequent transfer of an iodine atom or phenyl telluride group was used to develop a tin-freeradical acylation reaction (see scheme; V-40=1,1'-azobis(cyclohexane-1-carbonitrile). The key was finding reactionconditionsunder which the I or PhTe transfer is faster than the direct addition of the alkyl radical to the methanesulfonyl oxime
Nickel-Catalyzed Cross-Couplings of Organosilicon Reagents with Unactivated Secondary Alkyl Bromides
作者:David A. Powell、Gregory C. Fu
DOI:10.1021/ja047433c
日期:2004.6.1
A metal-catalyzed cross-coupling of organosilicon compounds with alkyl halides has been developed. Noteworthy attributes of the method are its scope (secondary electrophiles), its high functional-group compatibility, and the air stability of the catalyst components.
Heavy metals can be avoided with a newradical equivalent of the Heck reaction for aliphatic derivatives in which iodide and dithiocarbonate substituents are replaced by substituted vinyl groups [Eq. (1)]. The reaction enables the introduction of vinyl fragments into a variety of functionalized substrates.
Enantioselective Iodolactonization of Disubstituted Olefinic Acids Using a Bifunctional Catalyst
作者:Chao Fang、Daniel H. Paull、J. Caleb Hethcox、Christopher R. Shugrue、Stephen F. Martin
DOI:10.1021/ol3030555
日期:2012.12.21
The enantioselectiveiodolactonizations of a series of diversely substituted olefinic carboxylic acids are promoted by a BINOL-derived, bifunctional catalyst. Reactions involving 5-alkyl- and 5-aryl-4(Z)-pentenoic acids and 6-alkyl- and 6-aryl-5(Z)-hexenoic acids provide the corresponding γ- and δ-lactones having stereogenic C–I bonds in excellent yields and >97:3 er. Significantly, this represents
BINOL 衍生的双功能催化剂促进了一系列不同取代的烯烃羧酸的对映选择性碘内酯化。涉及 5-烷基-和 5-芳基-4( Z )-戊烯酸和 6-烷基-和 6-芳基-5( Z )-己烯酸的反应提供相应的具有立体异构 C-I 键的 γ-和 δ-内酯以优异的产量和 >97:3 er。值得注意的是,这代表了第一种以高对映选择性促进溴和碘内酯化的有机催化剂。还证明了该催化剂诱导外消旋不饱和酸的动力学拆分的潜力。