New Applications of 1,5-Hydrogen Atom Transfer Reactions: Self-Oxidizing Protecting Groups
作者:Dennis P. Curran、Hosung Yu
DOI:10.1055/s-1992-34173
日期:——
Three new alcohol protecting groups are introduced: o-bromobenzyl, o-bromo(methylenedioxy)benzyl, and o-bromotrityl. Removal of these protecting groups under reductive conditions with tributyltin hydride is coupled with an oxidation of the substrate to produce directly an aldehyde or ketone. This oxidation occurs by 1,5-hydrogen transfer, followed by ß-fragmentation. For example, treatment of the o-bromobenzyl ether of 3-phenyl-1-propanol with tibutyltin hydride at 0.001 M (80°C) directly produces 3-phenyl-1-propanal. An application to the selective oxidation of primary alcohols in the presence of secondary alcohols is also introduced.
The present disclosure is generally directed to antiviral compounds, and more specifically directed to combinations of compounds which can inhibit the function of the NS5A protein encoded by Hepatitis C virus (HCV), compositions comprising such combinations, and methods for inhibiting the function of the NS5A protein.
Two successful synthetic routes to trichostatin A (1) are described; one (Scheme 2) uses the γ-alkylation of a silyl dienol ether, the other (Scheme 4) uses a silyl-protected cyanohydrin anion. The two routes bear an upolung relation to each other. The Lewis acid-catalysed acylation of silyl enol ethers is a simple and effective way to prepare β-diketones and β-keto esters (Scheme 1); this reaction
Synthesis of carboxyalkylindolenines from 6-methyl-7-oxooctanoic acid
作者:V. E. Kuznetsova、A. V. Chudinov
DOI:10.1007/s11172-008-0095-7
日期:2008.3
Novel 3-(4-carboxybutyl)indolenines were obtained. A method for the synthesis of 6-methyl-7-oxooctanoic acid, the precursor for these indolenines, was developed.
Acylation of steroidal saturated ketones and their enol acetates with acetic anhydride and BF3-etherate has been studied. α-Acylketones were obtained from 3-keto, 7-keto and 16-keto steroids (I, XII and IX) in the A/B trans series and from 3-ketone (VI) in the A/B cis series. The intermediate difluoroboron chelates (II and VII) were isolated and characterized. No C-acylation of tertiary carbon atom