Abstract Dehydration of pentitols in acetic acid containing an acidic catalyst parallels that in aqueous sulfuric acid; 1,4(2,5)-dehydration occurs with inversion of configuration at C-2 or C-4. Acetylated alditols undergo similar processes via intermediates having free hydroxyl groups. Configurational inversion of 1,4- or 1,5-anhydroalditols is attributed to intermediate acyloxonium ions that are
An efficient synthesis of anhydroalditols and allylic-glycosides
作者:John A. Bennek、Gary R. Gray
DOI:10.1021/jo00381a030
日期:1987.3
Rhodium-Catalyzed Decarbonylation of Aldoses
作者:Rune Nygaard Monrad、Robert Madsen
DOI:10.1021/jo7017729
日期:2007.12.1
[Graphics]A catalytic procedure is described for decarbonylation of unprotected aldoses to afford alditols with one less carbon atom. The reaction is performed with the rhodium complex Rh(dPPP)(2)Cl in a refluxing diglyme-DMA solution. A slightly improved catalyst turnover is observed when a catalytic amount of pyridine is added. Under these conditions most hexoses and pentoses undergo decarbonylation into the corresponding pentitols and tetrols in isolated yields around 70%. The reaction has been applied as the key transformation in a five-step synthesis of L-threose from D-glucose.
Yabuta et al., Nippon Nogeikagaku Kaishi, 1941, vol. 17, p. 581,583