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.
This letter describes the synthesis of (±) cis-substituted cyclohexenyl and cyclohexanyl nucleosides. The synthesis of cis isomers was successfully achieved by the use of two consecutive Mitsunobu reactions involving an inversion of configuration and a sugar–base condensation.
Synthesis and Antiviral Evaluation of Cis-Substituted Cyclohexenyl and Cyclohexanyl Nucleosides
作者:Karine Barral、Jérôme Courcambeck、Gérard Pèpe、Jan Balzarini、Johan Neyts、Erik De Clercq、Michel Camplo
DOI:10.1021/jm0493966
日期:2005.1.1
Starting from commercially available (rac)-3-cyclohexene-1-carboxylic acid, a series of purine and pyrimidine cis-substituted cyclohexenyl and cyclohexanyl nucleosides were synthesized through a key Mitsunobu reaction. Antiviral evaluations were performed on HIV, coxsackie B3, and herpes viruses (HSV-1, HSV-2, VZV, HCMV). Three compounds showed moderate activity against HSV-1 and coxsackie viruses
Palladium‐Catalyzed Allylic Alkylation of 2‐Aryl‐1,3‐Dithianes, an Umpolung Synthesis of β,γ‐Unsaturated Ketones
作者:Nisalak Trongsiriwat、Minyan Li、Ana Pascual‐Escudero、Baris Yucel、Patrick J. Walsh
DOI:10.1002/adsc.201801035
日期:2019.2
at room temperature is described. A variety of cyclic and acyclic electrophiles successfully coupled with in‐situ generated 2‐sodio‐1,3‐dithiane nucleophiles to afford the allylated products in good to excellent yields (25 examples). Deprotection of these products leads to valuable β,γ‐unsaturated ketones. Direct synthesis of such β,γ‐unsaturated ketones via a one‐pot allylation‐oxidation protocol is