Carbonylation of cis-Disubstituted Epoxides to trans-β-Lactones: Catalysts Displaying Steric and Contrasteric Regioselectivity
摘要:
trans-beta-Lactones are a versatile and useful class of compounds, but reliable methods for their direct synthesis are still limited. Addressing this problem, we present herein two catalysts for the regioselective carbonylation of cis-disubstituted epoxides. The two catalysts show high activities and opposing regioselectivities so that either one of the two possible beta-lactone regioisomers can be obtained selectively.
Addition of arylstannanes to alkynes giving <i>ortho</i>-alkenylarylstannanes catalysed cooperatively by a rhodium complex and zinc chloride
作者:Jialin Ming、Qi Shi、Tamio Hayashi
DOI:10.1039/c8sc02459f
日期:——
The reaction of arylstannanes ArSnR3 with unfunctionalised alkynes was found to proceed in the presence of a rhodium catalyst and a catalytic amount of zinc chloride to give ortho-alkenylarylstannanes with high selectivity in high yields. The catalytic cycle is very unique, consisting of three transmetalation steps, from Sn to Rh, Rh to Zn, and Zn to Sn, in addition to arylrhodation of alkyne followed
Iron-catalyzed α-C–H functionalization of π-bonds: cross-dehydrogenative coupling and mechanistic insights
作者:Yidong Wang、Jin Zhu、Rui Guo、Haley Lindberg、Yi-Ming Wang
DOI:10.1039/d0sc05091a
日期:——
propargylic C–H bonds under mild, catalytic conditions. This technology was applied to the direct conversion of C–H bonds to C–C bonds for the synthesis of several functionalized scaffolds through a one-pot crossdehydrogenativecoupling reaction with tetrahydroisoquinoline and related privileged heterocyclic scaffolds. A series of NMR studies and deuterium-labelling experiments indicated that the deprotonation
Synthesis and SAR of Lehualide B: A Marine-Derived Natural Product with Potent Anti-Multiple Myeloma Activity
作者:Valer Jeso、Chunying Yang、Michael D. Cameron、John L. Cleveland、Glenn C. Micalizio
DOI:10.1021/cb300582s
日期:2013.6.21
that resemble verticipyrone (an established complex I inhibitor composed of a γ-pyrone and a simple monounsaturated hydrophobic chain) lack the potent antimyeloma activity of the natural product. Finally, the synthesis and evaluation of a collection of lehualide-inspired analogues led to the elucidation of structure–activity relationships for this rare natural product that established important roles for
我们报告了稀有海洋天然产物 lehualide B 的简明、收敛的实验室合成,结果发现 (1) 该化合物对人类多发性骨髓瘤细胞具有低纳摩尔活性,以及 (2) lehualide B 及其类似物的抗癌作用具有选择性(即,它们对人类乳腺癌细胞的毒性大约低 2-3 个数量级)。合成的 lehualide B 被证明是线粒体电子传递链复合物 I 的有效抑制剂,其效力类似于陆地天然产物 piericidin A1 和鱼藤酮,这一观察结果导致发现 piericidin A1 也具有选择性细胞毒性针对人类多发性骨髓瘤细胞。有趣的是,lehualide B 的合成衍生物类似于维替西吡隆(一种已确定的复合物 I 抑制剂,由 γ-吡喃酮和简单的单不饱和疏水链组成),缺乏天然产物的有效抗骨髓瘤活性。最后,一系列受 lehualide 启发的类似物的合成和评估阐明了这种稀有天然产物的结构-活性关系,确立了取代的
Cobalt-Catalyzed Regio- and Stereoselective Hydrosilylation of Alk-2-ynes with Tertiary Silanes
作者:Hongfang Li、Chengbo Yang、Dongyang Wang、Liang Deng
DOI:10.1021/acs.organomet.2c00563
日期:——
Selectivity control in the addition reactions of internal alkynes that bear two similar substituents presents a big challenge in modern organicsynthesis. Herein we report that β-(E)-selective hydrosilylation of alk-2-ynes with tertiary silanes can be achieved by using Co2(CO)8 as the catalyst. Under the catalytic reaction conditions, a wide range of alk-2-ynes can be converted into vinylsilanes with
带有两个相似取代基的内部炔烃加成反应的选择性控制对现代有机合成提出了巨大的挑战。在此我们报道了通过使用Co 2 (CO) 8作为催化剂可以实现烷-2-炔与叔硅烷的β-( E )-选择性氢化硅烷化。在催化反应条件下,多种烷-2-炔可以转化为乙烯基硅烷,其中β-( E )异构体作为主要或唯一的氢化硅烷化产物。机理研究表明炔桥二钴物质是可能的中间体。烯基桥联二钴甲硅烷基中间体中取代基之间的空间排斥被认为是引起观察到的区域选择性的关键因素。
Alkylidenecarbenes from acyclic vinyl bromides and potassium tert-butoxide
作者:Joseph Wolinsky、Gregory W. Clark、Patricia C. Thorstenson