Mild and Chemoselective Synthesis and Deprotection of Geminal Diacetates Catalyzed by Titanium(IV) Halides
作者:Jae-Sang Ryu、Misuk Jung、Jieun Yoon、Hak Kim
DOI:10.1055/s-0029-1218849
日期:2010.8
A novel, mild, and chemoselective method was developed for the preparation of gem-diacetates from aldehydes and acetic anhydride in the presence of titanium(IV) fluoride (1-5 mol%) under solvent-free conditions at room temperature. The reaction showed a high chemoselectivity toward aldehydes in the presence of ketones. Moreover, titanium(IV) fluoride also catalyzed the deprotection of gem-diacetates
Copper(II) Tetrafluoroborate-Catalyzed Formation of Aldehyde-1,1-diacetates<sup />
作者:Asit K. Chakraborti、Ramasamy Thilagavathi、Raj Kumar
DOI:10.1055/s-2004-816000
日期:——
Aldehyde 1,1-diacetates are formed in excellent yields from aldehydes and acetic anhydride under solvent-free conditions at room temperature in short times in the presence of a catalytic amount of copper(II) tetrafluoroborate hydrate.
Transition‐Metal‐Free Synthesis of Polyfunctional Triarylmethanes and 1,1‐Diarylalkanes by Sequential Cross‐Coupling of Benzal Diacetates with Organozinc Reagents
A variety of functionalized triarylmethane and 1,1‐diarylalkane derivatives were prepared via a transition‐metal‐free, one‐pot and two‐step procedure, involving the reaction of various benzal diacetates with organozincreagents. A sequential cross‐coupling is enabled by changing the solvent from THF to toluene, and a two‐step SN1‐type mechanism was proposed and evidenced by experimental studies. The
通过无过渡金属的一锅两步程序制备了各种官能化三芳基甲烷和1,1-二芳基烷烃衍生物,其中包括各种二乙酸苯亚缩酯与有机锌试剂的反应。通过将溶剂从 THF 更改为甲苯,可以实现顺序交叉偶联,并提出了两步 S N 1 型机理,并通过实验研究证明了这一点。该方法的合成效用通过几种生物学相关分子的合成得到进一步证明,例如抗结核剂、抗乳腺癌剂、鞘氨醇-1-磷酸(S1P)受体调节剂的前体和FLAP抑制剂。
Thallium(III) Chloride: A Mild
and Efficient Catalyst for Acylation of Alcohols, Phenols
and Thiols, and for Geminal Diacylation of Aldehydes under
Solvent-Free Conditions
作者:Sung Kim、Santosh Kadam
DOI:10.1055/s-0028-1083148
日期:——
simple and efficientcatalyst for acylation of alcohols, phenols and thiols. It is also very effective for geminal diacylation of aldehydes. The acylation reaction using acetic anhydride proceeds in excellent yield in the presence of catalytic amounts ofthallium(III) chloride (1 mol%) at room temperature within relatively short reaction times (<20 min). Structurally diverse alcohols, phenols, thiols and
CARO'S ACID SUPPORTED ON SILICA GEL. PART VI. A MILD REAGENT FOR REGENERATION OF CARBONYL COMPOUNDS FROM ACETALS, KETALS, AND 1,1-DIACETATES
作者:M. M. Lakouraj、M. Tajbakhsh、V. Khojasteh、M. H. Gholami
DOI:10.1080/10426500490494750
日期:2004.12.1
Efficient conversion of acetals, ketals, and diacetates to carbonylcompounds is described using Caro's acid supported on silica gel. The deacetalization reactions are carried out in acetonitrile at room temperature. Reaction of diacetates is performed in refluxing dichloromethane, and their parent carbonylcompounds are obtained in good-to-excellent yields.
使用负载在硅胶上的 Caro 酸描述了缩醛、缩酮和二乙酸酯向羰基化合物的有效转化。脱缩醛反应在室温下在乙腈中进行。双乙酸酯在回流二氯甲烷中反应,得到母体羰基化合物,产率从优到优。