Ethyl dichloro(ethoxy)acetate (1) and methyl dichloro(methoxy)acetate (2) were characterized. The reaction of 1 and 2 with aromatics in the presence of AlCl3 gave a considerable yield of aromatic α-keto ester. The aromatics included mono- and polymethylbenzene and anisol. The reaction was studied under various conditions and the results were compared with the acylation by ethoxalyl or methoxalyl chloride
Chiral aminoalcohol promoted one-pot addition of zinc alkynylides to α-keto esters and kinetic resolution of the resulting tertiary propargylic alcohols was developed. The reaction provided us an alternative approach to access optically activetertiary α-hydroxy-β-ynyl esters with enantiomeric excesses up to 98%.
3-hydroxyoxindoles through tandem photoredox and chiral phosphoric acid catalysis is developed. The reaction involves an enantioselective photochemical radical–radicalcross-coupling process. The chiral phosphoric acid is discovered to play crucial roles by decreasing the reductive potentials of α-ketoesters and stereocontrolling the downstream asymmetricradical–radicalcross-coupling via the formation
In prime condition: The hydrolysis of a chiral diimine precursor can be carried out by a Brønsted acid to form an in situprimaryamine–imine intermediate as a bifunctionalprimary aminocatalyst, which promoted direct asymmetricaldolreactions between α‐keto esters and ketones in high yields (up to 88 %) and with excellent enantioselectivities (see scheme; R1, R2, R4=alkyl; R3=aryl).
在最佳条件下:手性二亚胺前体的水解可通过布朗斯台德酸进行,形成原位伯胺-亚胺中间体,作为双官能伯氨基催化剂,从而促进α-酮酯与酮之间的直接不对称醛醇缩合反应。产率(高达88%)并且具有优异的对映选择性(参见方案; R 1,R 2,R 4=烷基; R 3=芳基)。
Methyl Benzoylformate Derivative Norrish Type I Photoinitiators for Deep-Layer Photocuring under Near-UV or Visible LED
作者:Xianglong He、Yanjing Gao、Jun Nie、Fang Sun
DOI:10.1021/acs.macromol.0c02868
日期:2021.4.27
We designed and prepared a series of methyl benzoylformate (MBF) derivatives Norrish type I photoinitiators (MBFs) for light-emitting diode (LED)-induced photopolymerization through computer simulation. The potential photolysis mechanism of MBFs under LED at 405 nm was explored by steady-state photolysis, nuclear magnetic resonance, and electron spin resonance. The as-synthesized photoinitiator dimethyl