ISSN:
0018-019X
Keywords:
Chemistry
;
Organic Chemistry
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
In the presence of 2 mol-equiv. of AcONa, both triglycosylborane 1 and dicyclohexylglycosylborane 2 readily react with bromine chloride generated in situ from bromide and N-chlorosuccinimide (NCS) to give the bromo-sugar 3 (75 and 60%, resp.). The use of the BH3-THF/bromide/NCS/2 AcONa procedure permits the rapid, face-specific synthesis of 6 (58% uptake of bromine) and face-selective synthesis of 8/9 (71% uptake of bromine), from vinyl ether derivatives 5 and 7, respectively. The dicyclohexylborane/bromide/NCS/2 AcONa procedure leads to the fast and quantitative conversion of 11 to the bromosugar 12 (91%). Hydroboration-transmetallation sequences give access to C-mercuriated carbohydrates 13 (71%) and 14 (78%). The bis(glycosyl)mercury derivative 13 is spontaneously cleaved by reaction with one equivalent of bromide/chloramine-T/aqueous HCl-solution to give 3 (87%) and 14 (76%). Hydrostannylation of acetylenic sugar 15 gave the (E)-stannylvinyl derivative 16 as the major product. This latter precursor 16 is spontaneously cleaved by the bromide/chloramine-T/aqueous HCl-solution reagent to give the bromovinyl-sugar 17 (96%).
Additional Material:
1 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/hlca.19830660403
Permalink