Tandem catalysis for asymmetric coupling of ethylene and enynes to functionalized cyclobutanes
作者:Vinayak Vishnu Pagar、T. V. RajanBabu
DOI:10.1126/science.aat6205
日期:2018.7.6
chiral cyclobutane products. Transformation of simple precursors into structurally complex cyclobutanes, present in many biologically important natural products and pharmaceuticals, is of considerable interest in medicinal chemistry. Starting from 1,3-enynes and ethylene, both exceptionally inexpensive starting materials, we report a cobalt-catalyzed route to vinylcyclobutenes, as well as the further
作者:Karen M. Miller、Torsak Luanphaisarnnont、Carmela Molinaro、Timothy F. Jamison
DOI:10.1021/ja0491735
日期:2004.4.1
epoxides, the conjugated alkene dramatically enhances reactivity and uniformly directsregioselectivity, independent of the nature of the other alkyne substituent (aryl, alkyl (1 degrees , 2 degrees , 3 degrees )) or the degree of alkene substitution (mono-, di-, tri-, and tetrasubstituted). These observations are best explained by a temporary interaction between the alkene and the transition metal
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
Stereoselective Synthesis of Allenyl Alcohols by Cobalt(III)‐Catalyzed Sequential C−H Bond Addition to 1,3‐Enynes and Aldehydes
作者:Chaofan Xu、Joseph P. Tassone、Brandon Q. Mercado、Jonathan A. Ellman
DOI:10.1002/anie.202202364
日期:2022.6.20
An efficient and stereoselective Co-catalyzed three-component synthesis of allenyl alcohols is reported. This method introduces two C−C σ bonds through C−H bond activation and sequential addition to 1,3-enynes and a wide range of aldehydes. A plausible mechanism and further transformations are disclosed.