Journal article
Synthesis of carba sugars from aldonolactones. Part IV. Stereospecific synthesis of carbaheptopyranoses by radical-induced carbocyclisation of 2,3-unsaturated octonolactones
Three new carbaheptopyranoses, 6-deoxy-5a-carba-beta -L-gulo- (8), 5a-carba-D-glycero-beta -D-ido- (22) and 5a-carba-L-glycero-alpha -L-galacto-heptopyranose (25), have been prepared from 8-bromo-8-deoxy-2,3-unsaturated octono-1,4-lactones with L-galacto-, D-gluco- and D-manno-configuration, respectively.
The key step was a regio- and stereoselective 6-exo-trig radical-induced carbocyclisation of the unsaturated octonolactones to give bicyclic cyclohexane-lactone derivatives. Reduction of the lactone moiety using Ca(BH4)(2) gave the said carbaheptopyranoses. The 8-bromo-8-deoxy-2,3-unsaturated octonolactones were prepared from the inexpensive, commercially available D-glycero-D-gulo-heptonolactone and L-tartaric acid.
Language: | English |
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Year: | 2001 |
Pages: | 780-788 |
ISSN: | 14727781 , 0300922x and 13645463 |
Types: | Journal article |
DOI: | 10.1039/b100708o |