Highly Stereoselective Synthesis of Tetrasubstituted Acyclic All-Carbon Olefins via Enol Tosylation and Suzuki–Miyaura Coupling
作者:Beryl X. Li、Diane N. Le、Kyle A. Mack、Andrew McClory、Ngiap-Kie Lim、Theresa Cravillion、Scott Savage、Chong Han、David B. Collum、Haiming Zhang、Francis Gosselin
DOI:10.1021/jacs.7b05071
日期:2017.8.9
A highly stereocontrolled synthesis of tetrasubstituted acyclic all-carbon olefins has been developed via a stereoselective enolization and tosylate formation, followed by a palladium-catalyzed Suzuki-Miyaura cross-coupling of the tosylates and pinacol boronic esters in the presence of a Pd(OAc)2/RuPhos catalytic system. Both the enol tosylation and Suzuki-Miyaura coupling reactions tolerate an array
The α-alkylation of a broad range of methylene ketones was achieved using a ruthenium(II)-NHC catalyst under borrowing hydrogen conditions. Primary alcohols served as alkylating agents and could be used in a one-to-one stoichiometry with respect to the ketone. The selectivity of the process for methyl over branched ketones enabled a one-pot double alkylation protocol utilizing two different alcohols
Influence des substituants sur la vitesse de racémisation des cétones à carbone dissymétrique en alpha
作者:A. K. Mills、A. E. Wilder Smith
DOI:10.1002/hlca.19600430705
日期:——
The rates of racemisation, under constant conditions of pH and temperature, of two series of ketones with an asymmetric C-atom in α have been determined. As would be expected, substituents in the α position to the keto group influence the rate of racemisation, and it has been found possible to assess the relative electron donating or electron attracting effect of aliphatic, aliphatic-aromatic or aromatic
Expedient Synthesis of Ketones
<i>via</i>
<scp>
<i>N</i>
‐Heterocyclic
</scp>
Carbene/
<scp>Nickel‐Catalyzed Redox‐Economical</scp>
Coupling of Alcohols and Alkynes
<sup>†</sup>
作者:Yu‐Qing Li、Feng Li、Shi‐Liang Shi
DOI:10.1002/cjoc.202000019
日期:2020.10
N‐heterocyclic carbene/nickel‐catalyzed direct coupling of alcohols and internal alkynes to form α‐branched ketones has been developed. This methodology provides a new approach to afford branched ketones, which are difficult to access through the hydroacylation of simple internal alkenes with aldehydes. This redox‐neutral and redox‐economical coupling is free from any oxidative or reductive additives
Reaction of bromine with phenyl-substituted tertiary alcohols
作者:Douglas W. Grant、Roy Shilton
DOI:10.1039/p19740000135
日期:——
The reaction between bromine and 1,1-diphenylalkan-1-ols is shown to proceed by dehydration to an alkene, followed in aqueous acetic acid by formation of a bromohydrin which may then rearrange to a ketone. A number of new bromohydrins and bromoalkenes have been prepared.