The Efficiency of the Metal Catalysts in the Nucleophilic Substitution of Alcohols is Dependent on the Nucleophile and Not on the Electrophile
作者:Srijit Biswas、Joseph S. M. Samec
DOI:10.1002/asia.201201178
日期:2013.5
efficiency and selectivity to perform the desired substitution. Interestingly, the selectivity of the alcohols to produce the desired substitution products was found to be independent of the electrophilicity of the generated carbocations but highly dependent on the ease of formation of the cation. Catalysts based on iron(III), bismuth(III), and gold(III) show higher conversions for S‐, C‐, and N‐centered
Condensation of propargylic alcohols with 1,3-dicarbonyl compounds and 4-hydroxycoumarins in ionic liquids (ILs)
作者:Gopalakrishnan Aridoss、Kenneth K. Laali
DOI:10.1016/j.tetlet.2011.10.021
日期:2011.12
Propargylicalcohols are activated toward 1,3-diketones by Lewis or Brønstedacidic ionic liquids (ILs) without an added catalyst, but significantly better conversions are achieved with metallic triflates [in particular Sc(OTf)3 and Ln(OTf)3] and bismuth nitrate in imidazolium ILs. The scope of this condensation reaction was investigated with a variety of propargylicalcohols and a host of acyclic
Arylboronic Acid-Catalyzed Racemization of Secondary and Tertiary Alcohols
作者:Gregory R. Boyce、Stefania F. Musolino、Jianing Yang、Andrew D. Smith、James E. Taylor
DOI:10.1021/acs.joc.2c01602
日期:2022.10.7
The use of 2-carboxyphenylboronic acid (5 mol %) and oxalic acid (10 mol %) with 2-butanone as a solvent for the racemization of a range of enantiomerically pure secondary and tertiaryalcohols is demonstrated. The process is postulated to proceed via reversible Brønsted acid-catalyzed C–O bond cleavage through an achiral carbocation intermediate.
Electrophilic chemistry of propargylic alcohols in imidazolium ionic liquids: Propargylation of arenes and synthesis of propargylic ethers catalyzed by metallic triflates [Bi(OTf)3, Sc(OTf)3, Yb(OTf)3], TfOH, or B(C6F5)3
作者:Gopalakrishnan Aridoss、Viorel D. Sarca、James F. Ponder Jr、Jessica Crowe、Kenneth K. Laali
DOI:10.1039/c0ob00872a
日期:——
formed. Steric influence of the propargylic moiety on substrate selectivity is reflected in the lack of ortho propargylation for phenol and ethylbenzene by using propargylic alcohol Ia, and notable formation of the ortho isomer employing alcohol Ib. In the later case paraselectivity could be increased by running the reaction at r. t. for 10 h. The Bi(OTf)3-catalyzed reaction of 1,3-dimethoxybenzene with