Deuteration experiments on 2-lithiated oxazoles show a pKa dependent regioselectivity suggesting that the ring cleaved tautomer dominates the equilibrium. Transmetallation to the zinc derivative gives a species which behaves as a C2 ring closed nucleophile as judged by deuteration and palladium catalysed coupling experiments. These conclusions are supported by nmr spectroscopy studies of the metallated species.
Stereocontrolled Total Synthesis of (−)-Kaitocephalin
作者:Rishi G. Vaswani、A. Richard Chamberlin
DOI:10.1021/jo702329z
日期:2008.3.1
scalable synthetic route profits from the strategic utilization of substrate-controlled manipulations for the iterative installation of the requisite stereogenic centers. The key transformations include a diastereoselective modified Claisen condensation, a chemo- and diastereoselective reduction of a β-ketoester, and the substrate-directed hydrogenation of a dehydroamino ester derivative. During the course
Palladium-catalyzed coupling of vinylic halides, alkenes, and amines
作者:Richard C. Larock、Chi Tu
DOI:10.1016/0040-4020(95)00265-a
日期:1995.6
The palladium-catalyzed, three component coupling of vinylic halides, alkenes, and amines has been re-examined. The success of the cross-coupling of vinylic halides, alkenes and amines depends heavily on the structures of each of the three substrates, as well as the reaction conditions. The presence of water greatly improves the yield. Secondary amines give much better results than primary amines.
Catalytic Intermolecular Carboamination of Unactivated Alkenes via Directed Aminopalladation
作者:Zhen Liu、Yanyan Wang、Zichen Wang、Tian Zeng、Peng Liu、Keary M. Engle
DOI:10.1021/jacs.7b06520
日期:2017.8.16
unactivated alkenes proceeding via a Pd(II)/Pd(IV) catalytic cycle has been developed. To realize this transformation, a cleavable bidentate directing group is used to control the regioselectivity of aminopalladation and stabilize the resulting organopalladium(II) intermediate, such that oxidative addition to a carbon electrophile outcompetes potential β-hydride elimination. Under the optimized reaction conditions
已开发出通过 Pd(II)/Pd(IV) 催化循环进行的未活化烯烃的分子间 1,2-碳甲化反应。为了实现这种转变,使用可裂解的双齿导向基团来控制氨基钯化的区域选择性并稳定所得的有机钯 (II) 中间体,从而使碳亲电子试剂的氧化加成胜过潜在的 β-氢化物消除。在优化的反应条件下,范围广泛的氮亲核试剂和碳亲电试剂是该反应中相容的偶联伙伴,提供中等至高产率。该反应的产物可以很容易地转化为游离的 γ-氨基酸和 γ-内酰胺,它们都是药物分子和生物活性化合物中常见的结构基序。
Nickel-Catalyzed 1,2-Diarylation of Simple Alkenyl Amides
作者:Joseph Derosa、Roman Kleinmans、Van T. Tran、Malkanthi K. Karunananda、Steven R. Wisniewski、Martin D. Eastgate、Keary M. Engle
DOI:10.1021/jacs.8b11942
日期:2018.12.26
A nickel-catalyzed conjunctive cross-coupling of simple alkenyl amides with aryl iodides and arylboronic esters is reported. The reaction is enabled by an electron-deficient olefin (EDO) ligand, dimethyl fumarate, and delivers the desired 1,2-diarylated products with excellent regiocontrol. Under optimized conditions, a wide range of amides derived from 3-butenoic acid, 4-pentenoic acid, and allyl
报道了简单烯基酰胺与芳基碘化物和芳基硼酸酯的镍催化连接交叉偶联。该反应由缺电子烯烃 (EDO) 配体富马酸二甲酯实现,并提供具有出色区域控制的所需 1,2-二芳基化产物。在优化条件下,衍生自 3-丁烯酸、4-戊烯酸和烯丙胺的多种酰胺都是相容的底物。该方法代表了由天然酰胺官能团引导的区域控制 1,2-二芳基化的第一个例子。计算分析揭示了潜在的底物结合模式和 EDO 配体在还原消除步骤中的作用。
Reactions of alkylmercurials with heteroatom-centered acceptor radicals
作者:Glen A. Russell、Preecha. Ngoviwatchai、Hasan I. Tashtoush、Anna. Pla-Dalmau、Rajive K. Khanna
DOI:10.1021/ja00219a030
日期:1988.5
En particulier, reactivite relative de chlorures d'alkylmercures vis-a-vis de PhS • , PhSe • et I • generes a partir du disulfure de phenyle, diseleniure de phenyle et du β-iodo styrene ou du (diphenyl-1,1 iodo-2) ethylene
En 特别,反应性相对于 de PhS • , PhSe • et I • 与 de PhS • , PhSe • et I • 属 a partir du disulfure de phenyle, diseleniure de phenyle et du β-iodo 苯乙烯 ou du (diphenyl-1,1 iodo -2) 乙烯