Oxidative Fluorocyclization of Vinyl Azides Leading to 5-Azido,5-fluoro-1,3-oxolan-2-one
作者:Lin Li、Shanshan Cao、Fanyi Lin、Peiqiu Liao、Yongquan Ning
DOI:10.1002/ejoc.201901699
日期:2020.2.14
A new strategy for alkene difunctionalization that enables the in situ introduction of a leaving group, keeping the N3 group intact is described. This transformation provides access to a variety of 5‐azido,5‐fluoro‐ 1,3‐oxolan‐2‐one derivatives with broad substrate scope and good functional group tolerance in good to excellent yields.
Subtle Electronic Effects in Metal-Free Rearrangement of Allenic Alcohols
作者:Venkata R. Sabbasani、Phani Mamidipalli、Huijie Lu、Yuanzhi Xia、Daesung Lee
DOI:10.1021/ol400331r
日期:2013.4.5
and stereoselective rearrangement of allenic alcohols to (E,E)-1,3-dien-2-yl triflates and chlorides was developed under metal-free conditions. Subtle electronic effects of the alkyl and aryl substituents on the carbon bearing the hydroxyl group has a profound impact on the reaction rate and efficiency such that vinyl triflates were obtained from electron-deficient substrates and trimethylsilyl triflate
Gold-Catalyzed Double Spirocyclization of 3-Ene-1,7-diyne Esters to Dispiroheterocycles
作者:Jichao Chen、Zhen Liu、Andrés Felipe León Rojas、Weidong Rao、Philip Wai Hong Chan
DOI:10.1021/acs.orglett.4c00884
日期:2024.4.19
A synthetic method to prepare dispiroheterocycles containing two all-carbon quaternary centers efficiently that relies on the gold(I)-catalyzed doublespirocyclization of 3-ene-1,7-diyneesters is described. The suggested mechanism delineates a rare example of a dispirocyclization featuring two 1,n-acyloxy shifts comprising a 1,3-acyloxy migration and an interrupted 1,5-acyl migration that was achieved
Substrate‐Rhodium Cooperativity in Photoinduced
<i>ortho</i>
‐Alkynylation of Arenes
作者:Argha Saha、Animesh Ghosh、Srimanta Guin、Sanjib Panda、Dibya Kanti Mal、Abhirup Majumdar、Munetaka Akita、Debabrata Maiti
DOI:10.1002/anie.202210492
日期:2022.10.17
AbstractIn the realm of metallaphotocatalytic C−H activation strategy, the direct excitation of the transition metal which plays the dual role of light energy harnessing alongside performing the bond breaking and forming is a rare phenomenon. In this context we have developed the first photo‐induced Rh‐catalyzedortho‐alkynylation under ambient conditions without the requirement of silver salt, photocatalyst (PC) or any engineered substrate or catalyst. The transformation functions by the specific cooperative effect of a six‐membered rhodacycle which is the photo‐responsive species. The catalytic system allows the conjugation of arenes with sp3‐rich pharmacophoric fragments. The control experiments as well as the computational studies resolve the mechanistic intricacies for this transformation. An outer sphere electron transfer process from Rh to alkynyl radical is operative for the present photo‐induced transformation over the more common oxidative addition or 1,2‐migratory insertion pathways.