| Abstract
| - The synthesis of carbasugar analogues of methyl α-d-arabinofuranoside and methyl β-d-arabinofuranoside (3 and 4) is reported. The route developed involves the conversion of d-mannose into asuitably protected diene (13), which is then cyclized via olefin metathesis. The resulting cyclopentene(14) is stereoselectively hydrogenated to provide an intermediate that can be used for the synthesisof both targets. Through the use of NMR spectroscopy, we have probed the ring conformation of 3and 4, as well as the rotamer populations about the C4−C5 and C1−O1 bonds. These studies havedemonstrated that there are differences in ring conformation between these carbasugars and theirglycoside parents (1 and 2). However, only minor differences are seen in the rotameric equilibriumabout the C4−C5 bond in 3 and 4 relative to 1 and 2. In regard to the C1−O1 bond, NOE data from3 and 4 suggest that the favored position about this bond is similar to that in the glycosides; thatis, the methyl group is anti to C2. However, confirmation of this preference through measurementof 3JC,C between the methyl group and C2 or C4a was not successful.
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