Diastereo-differentiating cyclopropanation of a chiral enol ether: a simple method for the preparation of optically pure cyclopropyl ethers
作者:Takashi Sugimura、Masato Yoshikawa、Tohru Futagawa、Akira Tai
DOI:10.1016/s0040-4020(01)87920-5
日期:1990.1
Enol ether of cyclohexanone carrying 2,4-pentanediol(PD) or 2,6- dimethyl-3,5-heptanediol(DMHD) as a chiral auxiliary was subjected to diastereo-differentiating cyclopropanation. The highest diastereomer excess(d.e.) of the product was found to be 95.2% in the case of PD and over 99.5% in the case of DMHD. The enol ethers prepared from various ketones and DMHD were also cyclopropanated in giving cyclopropyl
An appropriate solvent to perform the original Simmons–Smith reaction was reinvestigated. Among available solvents, cyclopentyl methyl ether (CPME), a recently commercialized ethereal solvent, was found to be the best so far. Compared with Et2O under reflux – the commonest conditions – reaction completion in CPME at 50 °C was about 10 times faster. The product yields and selectivities were mostly identical
Diastereo-differentiating simmons-smith reaction using 2,4-pentanediol as a chiral auxiliary
作者:Takashi Sugimura、Tohru Futagawa、Akira Tai
DOI:10.1016/s0040-4039(00)82189-9
日期:1988.1
SUGIMURA, TAKASHI;FUTAGAWA, TOHRU;TAI, AKIRA, TETRAHEDRON LETT., 29,(1988) N 45, C. 5775-5778
作者:SUGIMURA, TAKASHI、FUTAGAWA, TOHRU、TAI, AKIRA
DOI:——
日期:——
Diastereo-Differentiation during 2,4-Pentanediol Tethered Simmons-Smith Type Cyclopropanation: Reaction Species of Hydroxyl Group Directed Zinc Carbenoid Addition
作者:Takashi Sugimura、Masato Yoshikawa、Miki Mizuguchi、Akira Tai
DOI:10.1246/cl.1999.831
日期:1999.8
The predominant formation methods for the diastereo-differentiating species of zinc carbenoid addition to the 1-cyclohexenyl ether carrying the 2,4-pentanediol moiety were established. The species were found to include two zinc atoms and one carbenoid carbon at the hydroxyl group.