Herein, we describe an intermolecular direct branched‐selective α‐alkylation of cyclicketones with simple alkenes as the alkylation agents. Through an enamine‐transition metal cooperative catalysis mode, the α‐alkylation is realized in an atom‐ and step‐economic manner with excellent branched selectivity for preparing β‐branched ketones. Employment of a pair of bulky Brønsted acid and base as additives
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
synthesis of various value-added chemicals using methanol, acetonitrile, acetic acid, acetone and ethyl acetate as the hydrogen source by coupling them with olefins over heterogeneous photocatalysts. A radical coupling mechanism was proposed for the hydrofunctionalization of olefins with methanol to higher aliphatic alcohols over the Pt/TiO2 catalyst as the model reaction. C–H bond cleavage and C–C bond formation
通过在异质光催化剂上将它们与烯烃偶联,开发了一种绿色策略来合成各种增值化学品,使用甲醇,乙腈,乙酸,丙酮和乙酸乙酯作为氢源。作为模型反应,提出了一种自由基偶联机理,用于在甲醇中通过Pt / TiO 2催化剂将烯烃与甲醇加氢官能化为高级脂肪醇。光生自由基与末端烯烃之间的C–H键断裂和C–C键形成是在单个反应中高效完成的。我们的方法在原子上是经济的,具有高的抗马尔可夫尼科夫区域选择性,并且在温和的反应条件下具有广阔的应用前景。
Hydrofunctionalization of Olefins to Higher Aliphatic Alcohols via Visible-Light Photocatalytic Coupling
作者:Jingxian Bao、Yonghui Fan、Shuyi Zhang、Liangshu Zhong、Minghong Wu、Yuhan Sun
DOI:10.1007/s10562-019-02737-3
日期:2019.6
visible-light photocatalytic coupling. This method employs cheap, readily available and abundant methanol as both the C1 feedstock and the hydrogen source under visible light irradiation over CdS photocatalyst. A wide scope of olefin substrates could be hydrofunctionalized successfully to the corresponding higher alcohols with high selectivity. Besides alcohol, acetone and acetonitrile can also couple
Amberlyst®-15: a reusable heterogeneous catalyst for the dehydration of tertiary alcohols
作者:Luís M.T. Frija、Carlos A.M. Afonso
DOI:10.1016/j.tet.2012.06.083
日期:2012.9
under mild conditions in the presence of Amberlyst®-15 (dry) (solid-supported sulfonic acid) to give predominantly the most stable alkene in very good yield. The dehydration of tertiary alcohol functionality occurs without observation of rearrangement and polymerization products, and with outstanding substrate tolerance, which include the NHCBz, NHBoc, OSEM, OTBDMS, OBOM and ethylene ketal functional