Two-way homologation of aliphatic aldehydes: Both one-carbon shortening and lengthening via the same intermediate
作者:Jae Won Yoo、Youngran Seo、Jong Beom Park、Young Gyu Kim
DOI:10.1016/j.tet.2019.130883
日期:2020.2
Aliphaticaldehydes can be homologated to both one-carbon shorter and one-carbon longer homologous carbonyl compounds through the 2–4 steps of reactions via the same intermediates, β,γ-unsaturated α-nitrosulfones, prepared from the proline-catalyzed sequential reactions of several aliphaticaldehydes with phenylsulfonylnitromethane. While the oxidative cleavage of the key intermediates gave one-carbon
The aminopropylated Silica-Gel hydrochloride (APSG.HCl) proved to be an efficient catalyst for the rapid conversion of carbonyl compounds in the corresponding acetals with high yields and in mild and selective conditions. In addition to the obvious advantages offered by heterogeneous catalysis, the present method results very useful when the presence of a weakly-acidic function chemically bonded on
Er(OTf)<sub>3</sub>as a Mild Cleaving Agents for Acetals and Ketals
作者:Antonio Procopio、Renato Dalpozzo、Antonio De Nino、Loredana Maiuolo、Monica Nardi、Antonio Tagarelli
DOI:10.1055/s-2004-815941
日期:——
Er(OTf) 3 is proposed as a very gentle Lewis acid catalyst in a chemoselective method for the cleavage of alkyl and cyclic acetals and ketals at room temperature in wet nitromethane is presented.
Cyanotrimethylsilane adds to some ⇌,β-unsaturated ketones in conjugate manner under the catalytic action of Lewis acids such as triethylaluminium, aluminiumchloride, and SnCl2. Hydrolysis of the products gives β-cyano ketones which are identical to the hydrocyanated products of the starting enones. The title silicon reagent reacts with acetals and orthoesters under the catalytic action of SnCI2 or BF3-OEt2
Electrogenerated Acid-Catalyzed Reactions of Acetals, Aldehydes, and Ketones with Organosilicon Compounds, Leading to Aldol Reactions, Allylations, Cyanations, and Hydride Additions
electrogenerated acid (EG acid) in the silicon-mediated acid-catalyzed reactions; e.g., aldol reactions, allylations, cyanations, and hydride additions is described. The aldol reaction of acetals 1 with enol trimethylsilyl ethers 3 and 1,2-bis(trimethylsiloxy)alkenes 4 gives the corresponding adducts 5 and 6, respectively. The reaction proceeds smoothly with EG acid derived from perchlorate salts such