Acetalization of aldehydes and ketones over H<sub>4</sub>[SiW<sub>12</sub>O<sub>40</sub>] and H<sub>4</sub>[SiW<sub>12</sub>O<sub>40</sub>]/SiO<sub>2</sub>
作者:Shen Zhao、Yueqing Jia、Yu-Fei Song
DOI:10.1039/c4cy00021h
日期:——
A Keggin cluster of H4[SiW12O40] (H-SiW12) has been developed to catalyze the acetalization of aldehydes and ketones under solvent-free conditions, and could be recycled at least ten times without an obvious decrease in catalytic activity.
provided. The C–H amination can provide the corresponding amino derivatives on a gram scale. Various methods for the cleavage of the sulfonimidoyl group to give the corresponding tert-butoxycarbonyl- or acetyl-protected optically pure amines are also described. An efficient asymmetric C–H amination of benzylic and allylic substrates, as well as of adamantane derivatives, through catalytic C–H insertion
RESIST COMPOSITION AND METHOD FOR PRODUCING RESIST PATTERN
申请人:SUMITOMO CHEMICAL COMPANY, LIMITED
公开号:US20210286261A1
公开(公告)日:2021-09-16
Disclosed is a resist composition including a compound represented by formula (I), a resin having an acid-labile group and an acid generator, the resin having an acid-labile group including at least one selected from the group consisting of a structural unit represented by formula (a1-1) and a structural unit represented by formula (a1-2):
Protection of ketones or aldehydes as 1,3-dioxolane derivatives proceeds within minutes at room temperature in the presence of N-hydroxybenzenesulfonamide, its O-benzyl derivative, or the tosyl analogue, in the absence of strong protonic acids, and in the presence of base (Et3N). Acid-sensitive groups such as O-THP, O-TBS, or N-Boc are unaffected.
appropriate tether securing intramolecular addition of the nitrene, the intermolecular C–H amination remains much less predictable. This study aims at addressing this issue by capitalizing on an efficient stereoselective nitrene transfer involving the combination of a chiral aminating agent 1 with a chiral rhodium catalyst 2. Allylic C–H amination of terpenes and enol ethers occurs with excellent yields as well