Multiply Unsaturated and ω‐Brominated β‐Ketothioesters for Synthesizing β‐Ketolactams and the Scaffolds of Fully Enolized N‐Hydroxy‐3‐(polyenoyl)pyridine‐2,4‐dione Natural Products
A Versatile Route to the Tulearin Class of Macrolactones: Synthesis of a Stereoisomer of Tulearin A
作者:Alexander L. Mandel、Véronique Bellosta、Dennis P. Curran、Janine Cossy
DOI:10.1021/ol900936t
日期:2009.8.6
A versatile synthetic approach to the tulearin class of macrolactones has been developed and deployed to make a stereoisomer of tulearin A. The knowledge gained about structure and synthesis will expedite the assignment of the stereostructure of this new anticancer agent.
已经开发并部署了一种用于 tulearin 类大环内酯的通用合成方法来制备 tulearin A 的立体异构体。获得的关于结构和合成的知识将加速这种新型抗癌剂立体结构的分配。
Palladium catalysed coupling of imidazoles to alkynyl and vinyl substrates
作者:Matthew D Cliff、Stephen G Pyne
DOI:10.1016/0040-4020(96)00823-x
日期:1996.10
Methods for preparing 4-substituted imidazoles from the palladium(0) catalysed couplings of N-protected 4-haloimidazoles with alkynes or alkynyl- and vinyltrialkyltin derivatives or from the coupling reactions of 4-trimethylstannylimidazole 9 with aryl and vinyliodides and bromides under Stille conditions is reported.
Stereoselective construction of 3-trifluoromethyl conjugated dienoates, trienoates or dienynoates was achieved from ethyl (Z)-4,4,4-trifluoro-3-iodobutenoate and alkenyltin or alkynyltin reagents through the Stille reaction or under HeckâSonogashira coupling conditions. Reduction of ethyl 3-trifluoromethyldienoates using DIBAL-H selectively yielded allylic alcohols and hydrolysis with lithium hydroxide yielded the corresponding acids.
(E)- or (Z)-Enynoic acids and (2E,4E)- or (2Z,4E)-dienoic acids can be obtained in good yields under mild conditions through palladium-catalysed cross coupling of (E)- or (Z)-3-iodoprop-2-enoic acid with alkynylzinc or vinyltin reagents.
Magnesium-Catalyzed Stereoselective Hydrostannylation of Internal and Terminal Alkynes
作者:Marc Magre、Marcin Szewczyk、Magnus Rueping
DOI:10.1021/acs.orglett.0c00184
日期:2020.2.21
A regio- and stereoselective magnesium-catalyzed hydrostannylation of internal and terminalalkynes has been developed. Excellent yields and selectivities are obtained for a wide range of terminal and internal symmetrical and unsymmetrical alkynes by using this alkaline earth metal catalyst as an effective alternative to transition metal catalysts.