Two carbon chain extensions using a Wittig reaction on both a 1-deoxy ribulose derivative and a C-2-branched erythrose derivative are reported. Subsequent dihydroxylation resulted in the synthesis of C-3 and C-4 methyl-branched sugar lactones, the useful synthetic building blocks. Control of the stereoselectivity of both the Wittig reaction and the dihydroxylation is investigated, and 3-C-methyl and 4-C-methyl d-altrono-1,4-lactones and d-glucono-1,4-lactone and 4-C-hydroxymethyl-d-altrono-1,4-lactone were synthesised. © 2009 Elsevier Ltd. All rights reserved.