Bismuth Oxide Perchlorate as a Highly Efficient Catalyst for Heteroatom Acylation Under Solvent-Free Conditions
作者:Asit K. Chakraborti、Rajesh Gulhane、Shivani
DOI:10.1055/s-2003-41442
日期:——
Bismuth oxide perchlorate efficiently catalyzes the acetylation of structurally diverse phenols, alcohols, thiols, and amines undersolventfree conditions. Sterically hindered and electron deficient phenols are acetylated in excellent yields with stoichiometric amounts of Ac 2 O at room temperature. Acylation of acid-sensitive alcohols is carried out efficiently without competitive side reactions
高氯酸铋在无溶剂条件下有效催化结构不同的酚、醇、硫醇和胺的乙酰化。空间位阻和缺电子酚在室温下用化学计量的 Ac 2 O 以极好的收率乙酰化。酸敏感醇的酰化可以有效地进行,没有竞争性副反应。光学活性底物被乙酰化,对光学纯度没有任何不利影响。
The reaction between acyl halides and alcohols: Alkyl halide vs. Ester formation
作者:Paolo Strazzolini、Angelo G. Giumanini、Giancarlo Verardo
DOI:10.1016/s0040-4020(01)80747-x
日期:1994.4
therefore, ester formation practically confined to a triggering role. But, in those cases where the cation is less easily formed, ester formation was favoured and, consequently, became the necessary elementary step towards alkylhalideformation. This final product, on the other hand, might be extremely slow to form in an SN2 reaction between the protonated ester function and the halideion. In these hnstances
Efficient
<i>O</i>
‐Acylation of Alcohols and Phenol Using Cp
<sub>2</sub>
TiCl as a Reaction Promoter
作者:María Jesús Durán‐Peña、José Manuel Botubol‐Ares、James R. Hanson、Rosario Hernández‐Galán、Isidro G. Collado
DOI:10.1002/ejoc.201600496
日期:2016.7
secondary, and tertiary alcohols, and phenol, into the corresponding esters at room temperature. The method uses a titanium(III) species generated from a substoichiometric amount of titanocene dichloride together with manganese(0) as a reductant, as well as methylene diiodide. It involves a transesterification from an ethyl ester, or a reaction with an acyl chloride. A radical mechanism is proposed
Bi(OTf)(3)-catalyzed acylation of alcohols with acidanhydride was evaluated in comparison with other acylation methods. The Bi(OTf)(3)/acidanhydride protocol was so powerful that sterically demanding or tertiary alcohols could be acylated smoothly. Less reactive acylation reagents such as benzoic and pivalic anhydride are also activated by this catalysis. In these cases, a new technology was developed
1-phenylallyl pivalates was developed through reductive C(sp3)–Obondcleavage. This method represents the first example of the direct application of vastly abundant calcium granules to a reductive coupling reaction. A broad range of propargylsilanes and allylsilanes are simply prepared using easy-to-handle pivalates and chlorotrimethylsilane under mild catalyst-free and additive-free conditions.