Kinetic Enzymatic Resolution of Cyclopropane Derivatives
作者:Jörg Pietruszka、Anja C. M. Rieche、Thorsten Wilhelm、Andreas Witt
DOI:10.1002/adsc.200303137
日期:2003.12
enzymatic resolution of various cyclopropane derivatives was systematically investigated. The study focused on synthetically useful cyclopropylmethanols (e.g., 18a/j or 19a/j) as well as some rarely investigated cyclopropanols (e.g., 24/25 or 27). The combination of enantioselective catalytic or diastereoselective synthesis of enantiomericallyenriched compounds with enzymatic approaches ultimately
Diastereoselective Synthesis of Cyclopropyl Boronic Esters
作者:Jörg Pietruszka、Markus Widenmeyer
DOI:10.1055/s-1997-5790
日期:1997.8
The conversion of simple 1-alkynes to optically active 2-alkyl-cyclopropan-1-ols is conveniently achieved by a simple protocol. The key step is the cyclopropanation of alkenyl boronic esters derived from (+)-diisopropyl L-tartrate and alkenyl boronic acids. It has been found that best yields could be obtained using diazomethane and palladium(II) acetate as catalyst. The systematic investigation of parameters influencing this reaction led to an improvement of the diastereoselectivity of the transformation.
Chirality transfer from silicon to carbon via diastereoselective Simmons–Smith cyclopropanation of chiral alkenylsilanols
作者:Yuichi Yamamura、Fumihiko Toriyama、Tatsuhiro Kondo、Atsunori Mori
DOI:10.1016/s0957-4166(02)00056-3
日期:2002.2
Simmons–Smithcyclopropanation of a chiral alkenylsilanol with CH2I2–Et2Zn proceeds diastereoselectively to give the corresponding cyclopropylsilanol product. Chirality transfer from silicon to the alkenyl carbons of the silicon substituent is observed. The stereochemistry of the obtained cyclopropylsilanol is confirmed by converting to cyclopropanol via Tamao oxidation.
Simmons-Smith手性烯基硅烷醇与CH 2 I 2 -Et 2 Zn的环丙烷化非对映选择性,得到相应的环丙基硅烷醇产物。观察到从硅到硅取代基的烯基碳的手性转移。通过经由Tamao氧化转化为环丙醇,证实了所获得的环丙基硅烷醇的立体化学。
Asymmetric cyclopropanation of 1-alkenylboronic esters and its application to the synthesis of optically active cyclopropanols