122921-07-7Relevant articles and documents
Organotitanium-induced stereoselective alkylative endo-cleavage of benzyl pentopyranosides
Olsson, Roger,Rundstroem, Pontus,Persson, Bjoern,Frejd, Torbjoern
, p. 13 - 18 (1998)
The results presented are the first examples where organotitanium reagents induced alkylative endo-cleavage of carbohydrates. The best conditions for the alkylative transfer of a methyl group to benzyl 2-deoxy- 2-C-methyl-4-O-(tert-butyldimethylsilyl)-α-D-arabinopyranoside (1) were the application of one equivalent of AlMe3 followed by four equivalents of MeTiCl3 generated by mixing TiCl4 and ZnMe2 in a ratio 2:1, or, alternatively, treatment of I with two equivalents of 1:1 Me2TiCl2-ZnMe2. Both the yields and diastereoselectivities were comparable with those of the reaction with AlMe3 but the titanium reagents were more reactive and could be applied at much lower temperatures than the aluminium reagent.
Endocyclic cleavage of glycosides. VI. Substituent effects of the alkylative endocyclic cleavage of glycosides
Olsson, Roger,Berg, Ulf,Frejd, Torbjoern
, p. 3935 - 3954 (2007/10/03)
A number of pentopyranoside derivatives were treated with Me3Al in order to investigate the influence of structural parameters on the methyl group transfer in the endocyclic alkylative cleavage reaction of these substrates. A cyclic CH ··· O hydrogen bonded model is suggested as an intermediate, which is used to explain the stereoselectivities for different substrates. In several, cases the diastereoselectivities were better than 9:1.
Organoaluminium induced ring-opening of epoxypyranosides. IV. Synthesis and structure of γ-hydroxy-Isoleucine stereoisomers and their corresponding lactones
Inghardt, Tord,Frejd, Torbjoern,Svensson, Goeran
, p. 6469 - 6482 (2007/10/02)
Two γ-hydroxy-isoleucine stereoisomers 8 (2R, 3R, 4R), and 14 (2S, 3R, 4R) as well as their corresponding γ- lactones 9 and 15 were synthesized using a tandem. Me3Al induced opening of the epoxide and pyranoside rings of benzyl 2,3-anhydro-4-O-(tert-butyldimethylsilyl)-β-L-ribopyranoside (1). The structure of the lactone hydrochloride 9 was confirmed by an X-ray crystal structure determination.
Organoaluminum-Induced Opening of the Pyranosidic Ring of Benzyl 2-Deoxy-2-C-methylpentopyranosides
Inghardt, Tord,Frejd, Torbjoern
, p. 5539 - 5543 (2007/10/02)
Benzyl 2-deoxy-2-C-methylpentopyranosides ring open via attack at the anomeric carbon by the nucleophilic part of organoaluminum reagents (Me2AlR) to give chiral, partially protected, branched 1,2,3,5-tetrol derivatives 13-32.The reaction represents a direct chain extension of the glycosides at C-1.