Gold(<scp>i</scp>)-catalyzed addition of aldehydes to cyclopropylidene bearing 6-aryl-1,5-enynes
作者:Christina A. Roselli、Michel R. Gagné
DOI:10.1039/c6ob02128j
日期:——
cascading cycloisomerization of alkylidene cyclopropane bearing 1,5-enynes that terminates in a cyclo-addition of aldehydes has been developed. This diastereoselective reaction provides convergent access to novel polycyclic molecular structures (18 examples), and tolerates a diverse scope of aldehydes. Mechanistic studies reveal that the catalytic cycle rests at a digold off-cycle intermediate, one of which
Gold-Catalyzed Diastereoselective Cycloisomerization of Alkylidene-Cyclopropane-Bearing 1,6-Diynes
作者:Hongchao Zheng、Laura L. Adduci、Ryan J. Felix、Michel R. Gagné
DOI:10.1002/anie.201405147
日期:2014.7.21
AbstractAn unprecedented gold‐catalyzed diastereoselective cycloisomerization of 1,6‐diynes bearing an alkylidene cyclopropane moiety has been developed. This methodology enables rapid access to a variety of 1,2‐trimethylenenorbornanes, which are important building blocks in the preparations of abiotic and sesquiterpene core structures.
Gold-Catalyzed Enantioselective Ring-Expanding Cycloisomerization of Cyclopropylidene Bearing 1,5-Enynes
作者:Hongchao Zheng、Ryan J. Felix、Michel R. Gagné
DOI:10.1021/ol5007955
日期:2014.4.18
An enantioselective ring-expanding cycloisomerization of 1,5-enynes bearing a cyclopropylidene moiety has been developed. This methodology provides a new approach to bicyclo[4.2.0]octanes, a structural motif present in many biologically active natural products.
PtCl<sub>2</sub>-Catalyzed Rearrangement of Methylenecyclopropanes
作者:Alois Fürstner、Christophe Aïssa
DOI:10.1021/ja061392y
日期:2006.5.1
Alkylidenecyclopropanes readily convert into cyclobutene derivatives on treatment with catalytic amounts of PtCl2. The reaction is strongly accelerated when performed under an atmosphere of CO (1 atm). The resulting cyclobutenes are isolated in good to excellent yields for substrates bearing aliphatic as well as aromatic substituents R on their olefinic site. If the substituent R, however, is a very
亚烷基环丙烷在用催化量的 PtCl2 处理后很容易转化为环丁烯衍生物。当在 CO (1 atm) 气氛下进行时,反应会大大加速。对于在其烯属位点上带有脂肪族和芳香族取代基 R 的底物,所得环丁烯的分离产率良好至极好。但是,如果取代基 R 是非常富电子的芳烃,则最初形成的环丁烯会进一步反应生成二聚产物,其中含有以前未知的 1,2,2a,7a-四氢螺[环丁[a]茚-7,1'-环丁烷骨架。提出了解释这些实验观察以及氘标记实验的机制,这意味着非经典阳离子/卡宾界面处的反应性中间体。此外,还表明 PtCl2 催化的环丁烯形成可以与随后的开环/闭环复分解 (ROM/RCM) 事件相适应。最后,提出了一种方便的“一锅”方法,用于制备本研究中使用的亚烷基环丙烷底物,该方法基于改进的 Julia-Kocienski 醛烯化与现成的 1-叔丁基-1H-四唑-5- Barbier条件下的基-环丙基砜。
En Route to 2-(Cyclobuten-1-yl)-3-(trifluoromethyl)-1<i>H</i>-indole
A six-step synthetic route from 4-chloro-2-methylaniline to 5-chloro-2-(cyclobut-1-en-1-yl)-3-(trifluoromethyl)-1H-indole (1) has been reported. Compound 1a is a key impurity of reverse transcriptase inhibitor efavirenz, an important anti-HIV/AIDS drug. Synthetic challenges, dead ends, and detours are discussed.