Transition-Metal-Free Synthesis of Electron Rich 1,3-Dienes via Base Promoted Isomerization of Propargylic Ethers
作者:Chunxiang Liu、Guogang Deng、Xin Li、Yiren Xu、Kaili Yu、Wen Chen、Hongbin Zhang、Xiaodong Yang
DOI:10.1002/ejoc.201901743
日期:2020.1.31
An efficient and broadly applicable method for the construction of functionalized electron rich 1,3‐dienes through a base promoted isomerization reaction of propargylic ethers is presented. This process features easy handling reaction conditions, transition‐metal‐free isomerization, high isolated yields, and most of all, it could be used for late stage modification of natural products.
In the presence of phosphine catalyst and pinacolborane, ynones undergo 1,2-reduction while ynoates undergotrans-hydroboration. Mechanistic insights into the two competing pathways lay grounds for control of selectivity in these processes.
Intercepting the Banert cascade with nucleophilic fluorine: direct access to α-fluorinated <i>N</i>H-1,2,3-triazoles
作者:J. R. Alexander、P. V. Kevorkian、J. J. Topczewski
DOI:10.1039/d1cc01179k
日期:——
The treatment of propargylic azides with silver(I) fluoride in acetonitrile was found to yield α-fluorinated NH-1,2,3-triazoles via the Banert cascade. The reaction was regioselective and the products result from an initial [3,3] rearrangement. The reaction is demonstrated on >15 examples with yields ranging from 37% to 86%.
Synthesis of highly substituted allylic alcohols by a regio- and stereo-defined CuCl-mediated carbometallation reaction of 3-aryl-substituted secondary propargylic alcohols with Grignard reagents
作者:Xiaobing Zhang、Zhan Lu、Chunling Fu、Shengming Ma
DOI:10.1039/b903769a
日期:——
A highly regio- and stereoselective CuCl-mediated carbometallation reaction of 3-aryl-substituted secondary propargylicalcohols with alkyl, aryl, vinyl or allyl Grignard reagents for the synthesis of fully-substituted allylic alcohols was developed. The R2group from the Grignard reagent was successfully introduced to the 2-position of the propargylicalcohols due to the chelation of metal atom with
Facile synthesis of substituted thiophenes via Pd/C-mediated sonogashira coupling in water
作者:Sirisilla Raju、P. Rajender Kumar、K. Mukkanti、Pazhanimuthu Annamalai、Manojit Pal
DOI:10.1016/j.bmcl.2006.09.041
日期:2006.12
The first successful Pd/C-mediated Sonogashira coupling of iodothiophene with terminal alkynes in water is described here. Pd/C-CuI-PPh(3) was found to be an efficient catalyst system for this coupling reaction. Using this economic and reliable process a variety of acetylenic thiophenes with a wide range of functional groups were prepared in good yields. Synthetic applications and in vitro anticancer