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
Synthesis of Enantioenriched Allenes from 1,1-Cyclopropanediesters
作者:Pascal Cérat、Philipp J. Gritsch、Sébastien R. Goudreau、André B. Charette
DOI:10.1021/ol902766f
日期:2010.2.5
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.
Pd-Catalyzed Cascade Cyclization by Intramolecular Heck Insertion of an Allene–Allylic Amination Sequence: Application to the Synthesis of 3,4-Fused Tricyclic Indoles
A novel Pd-catalyzed cascade cyclization by intramolecular Heck insertion of an alleneallylic amination sequence was developed. Allenes tethered to ortho-iodoaniline derivatives at the meta-position were reacted with 5-10 mol % of Pd catalyst and 4 equiv of K2CO3 in DMSO at 90 degrees C, producing 3,4-fused tricyclic 3-alkylidene indoline derivatives in moderate to excellent yield. The reaction products were divergently transformed into three types of 3,4-fused tricyclic indole derivatives, successfully demonstrating the versatile properties of the reaction products.