Copper-catalysed, diboron-mediated <i>cis</i>-dideuterated semihydrogenation of alkynes with heavy water
作者:Xiaowei Han、Jiefeng Hu、Cheng Chen、Yu Yuan、Zhuangzhi Shi
DOI:10.1039/c9cc03213d
日期:——
efficiently mediate the transfer of two D atoms from heavy water directly onto alkynes through copper-catalysed cis-selective semihydrogenation. Avoiding the use of costly and flammable D2 gas, this safe and practical process can proceed with excellent chemoselectivity and stereoselectivity. Utilizing the present method as the key step, the formal asymmetrictotalsynthesis of d2-deuterium-labeled cis-combretastatin
The present invention is concerned with novel sulfuric acid esters of sugar alcohols and sugar alcohol-like compounds of the formula ##STR1## Also described are methods for the treatment and/or prophylaxis of arteriosclerotic changes in the vascular wall as well as a process for the manufacture of the compounds of formula I and their salts.
Ruthenium(II) porphyrin catalyzed cyclopropanation of alkenes with tosylhydrazones
作者:Jun-Long Zhang、Philip Wai Hong Chan、Chi-Ming Che
DOI:10.1016/j.tetlet.2003.09.157
日期:2003.11
The diastereoselective ruthenium(II) porphyrincatalyzed cyclopropanation of a variety of alkenes with aryl diazomethanes generated in situ from stable tosylhydrazone derivatives, was achieved in good to excellent yields (up to 92%) and product turnovers. The practical utility of [RuII(p-Cl-TPP)(CO)] (H2(p-Cl-TPP)=meso-tetrakis(p-chlorophenyl)porphyrin) 3 was illustrated in the synthesis of the potent
A novel [2.2]metacyclophane in which two benzene rings are linked together with a carbon–carbon double bond and a disilane unit was prepared. Photolysis of the cyclophane in the presence of oxygen afforded the 4,5-dihydro-4,5-disilapyrene derivative via a transannular dehydrogenation reaction.
Magnetic coupling between two phenoxyl radicals attached to the phenyl rings ofCIS- andtrans-stilbenes
作者:Teruyuki Mitsumori、Noboru Koga、Hiizu Iwamura
DOI:10.1002/poc.610070108
日期:1994.1
Magnetic coupling between two sterically protected phenoxylradicals through the cis- and trans-stilbene chromophores was studied by means of their EPR fine structures. While the zero-field splitting parameters D, which are governed by the magnitude of dipolar coupling, were dependent on the geometrical isomerism, the sign of exchange coupling was independent of it and dictated by the topology of the