An efficient high-yield synthesis of D-ribo-phytosphingosine

[4R-[4 alpha(S*),5 alpha]]-2,2-Dimethyl-4-(2-oxo-5-vinyl[1,3]dioxolan-4-yl) oxazolidine-3-carboxylic acid tert-butyl ester 5a, obtained in excellent yield and diastereoselectivity by the r-hydroxyallylation of the Garner aldehyde (4), is exploited in a novel high-yield synthesis of D-ribo-phytosphingosine (8), using microwave-enhanced cross metathesis as the key step in the chain elongation.