Phenol-Catalyzed Thione-Thiol Rearrangement of Xanthates and Modified Intermediate Neglect of Differential Overlap(MINDO/3) Analysis of the Reaction Mechanism.
作者:Kazunobu HARANO、Hideo KIYONAGA、Takuzo HISANO
DOI:10.1248/cpb.40.2654
日期:——
S-Alkyl dithiocarbonates (xanthates) of alkanols containing strained σ bonds underwent rearrangement to S, S-dialkyl dithiocarbonates, catalyzed by phenolic compounds. The reaction followed first-order kinetics and the rates were affected by the acidity of the phenols. The rate contants are proportional to the square of the concentration of phenol.The modified intermediate neglect of differential overlap (MINDO/3) geometry optimization indicates that S, S-dialkyl dithiocarbonate is ca. 9 kcal/mol more stable than O, S-dialkyl xanthate. The thione-thiol rearrangement and sulfide formation reactions were analyzed by MO simulations. The experimental results can be well reproduced by the MINDO/3 method rather than the modified neglect of diatomic overlap (MNDO) method. Based on these data, the reaction mechanism is discussed.
HARANO KAZUNOBU; KIYONAGA HIDEO; HISANO TAKUZO, CHEM. AND PHARM. BULL., 35,(1987) N 4, 1388-1396
作者:HARANO KAZUNOBU、 KIYONAGA HIDEO、 HISANO TAKUZO
DOI:——
日期:——
Deoxygenative Borylation of Secondary and Tertiary Alcohols
作者:Florian W. Friese、Armido Studer
DOI:10.1002/anie.201904028
日期:2019.7.8
Two different approaches for the deoxygenative radical borylation of secondary and tertiary alcohols are presented. These transformations either proceed through a metal‐free silyl‐radical‐mediated pathway or utilize visible‐light photoredox catalysis. Readily available xanthates or methyl oxalates are used as radical precursors. The reactions show broad substrate scope and high functional‐group tolerance