Synthesis of 4-C-(1-hydroxyethyl) derivatives from benzyl 2,3-di-O-benzyl- and -2,3-O-methylene-β-l-threo-pentopyranosid-4-ulose, and the corresponding α-d-xylo-hexopyranosid-4-uloses
The stereoselectivities in the 1,2-addition of nucleophiles such as methylmagnesiumiodide, vinylmagnesium bromide, and 2-lithio-2-methyl-1,3-dithiane to seven kinds of 4-uloses were examined. The configurations of C-vinyl derivatives obtained were determined from the chemical shifts of α-carbons in 13C-NMR spectra.