Synthesis of Enantioenriched Allenes from 1,1-Cyclopropanediesters
摘要:
Highly substituted allenes were obtained by the S(N)2' addition of organocuprate reagents on 2-propargyl-1,1-cyclopropanediesters. This new methodology permits the synthesis of highly enantioenriched allenes as the reaction proceeds with retention of the enantiomeric purity of the starting cyclopropane. The use of higher order cuprates was instrumental in obtaining the reported results.
Palladium(0)–Lithium Iodide Cocatalyzed Asymmetric Hydroalkylation of Conjugated Enynes with Pronucleophiles Leading to 1,3-Disubstituted Allenes
作者:Hirokazu Tsukamoto、Tatsuya Konno、Kazuya Ito、Takayuki Doi
DOI:10.1021/acs.orglett.9b02439
日期:2019.9.6
reaction) with pronucleophiles such as dimethyl malonate under the cocatalysis of DTBM-SEGPHOS-ligated palladium and lithium iodide. Although the palladium catalyst ligated with (S)-DTBM-SEGPHOS prefers the formation of (R)-1,3-disubstituted allenes, lithium iodide recovers and increases the intrinsic selectivity producing (S)-allenes by promoting the isomerization of the exo-alkylidene-π-allylpalladium