Regioselective Sulfonylation/Acylation of Carbohydrates Catalyzed by FeCl<sub>3</sub> Combined with Benzoyltrifluoroacetone and Its Mechanism Study
作者:Jian Lv、Jia-Jia Zhu、Yu Liu、Hai Dong
DOI:10.1021/acs.joc.9b03128
日期:2020.3.6
A catalyticamount of FeCl3 combined with benzoyl trifluoroacetone (Hbtfa) (FeCl3/Hbtfa = 1/2) was used to catalyze sulfonylation/acylation of diols and polyols using diisopropylethylamine (DIPEA) or potassium carbonate (K2CO3) as a base. The catalytic system exhibited high catalytic activity, leading to excellent isolated yields of sulfonylation/acylation products with high regioselectivities. Mechanism
A substoichiometric amount (10-20 mol%) of dibutyltin dichloride 1 was found to be effective for promoting the regioselective 2'-O-tosylation of adenosine 2 with TsCl in a one-pot manner, wherein a turnover step for tin dichloride 1 was involved. Dibutylchlorotin hydroxide 7, dibutyltin oxide 8, bis(dibutylchlorotin) oxide 10, its hydroxy congener 12, and tributyltin chloride 14 were also effective ina substoichiometric amount for the 2'-O-tosylation of the nucleoside 2. The method was applicable to some methyl glycopyranosides, The tosylation with tin dichloride 1 was not sensitive to the presence of water in the reaction mixture. Possible reaction pathways are discussed.
Partial tosylation of methyl α-d-mannopyranoside
作者:Yôtaro Kondo
DOI:10.1016/s0008-6215(00)90046-6
日期:1986.10
Effective Organotin-Mediated Regioselective Functionalization of Unprotected Carbohydrates
作者:Yixuan Zhou、Kuo-Shiang Liao、Tzu-Yin Chen、Yves S. Y. Hsieh、Chi-Huey Wong
DOI:10.1021/acs.joc.3c00397
日期:2023.6.2
carbohydrates. The counteranion of tetrabutylammonium ion with a weak coordination ability plays a crucial role in the improved regioselective reactions. A convenient access to the intermediates of synthetic value is also demonstrated in the organotin-mediated regioselective tosylation of unprotected carbohydrates, followed by the nucleophilic inversion reaction to give sulfur-containing and azide-modified