The fucofuranoside method for determining the absolute configuration of the tertiary alcohols substituted with methyl and two methylene groups

The fucofuranoside method, a recently devised new method for determining the aboslute configuration of secondary alcohols, by derivatizing to beta-D- and beta-L-fucofuranosides, is applied to six chiral tertiary alcohols (1 to 6) substituted with methyl and two methylene groups. The Delta delta values (delta(L) - delta(D)) of the protons and carbons are derived from the H-1 and C-13 NMR spectra in pyridine-d(5). When the compounds are viewed placing the furanosyl group in front and the methyl group below (Fig. 1B), the following generalizations are derived. (a) In the H-1 NMR, the Delta delta(H) values are positive for the proximate protons in the right segment (R-r) and negative for the proximate protons in the left segment (R-1) (Fig. 2). (b) In the C-13 NMR, the Delta delta(C), values are positive for the right beta-carbon and negative for the left beta-carbon, except for the five-membered compound 5, which gave an ambiguous result (Fig. 3). (C) 1998 Elsevier Science Ltd. All rights reserved.