Ascent of the Aldose Series by Four Carbon Atoms: Total Synthesis of D-glycero-D-talo-L-talo-Undecose Pentaacetonide

Article abstract of DOI:10.1021/jo00006a032

Enantiomerically pure undecose acetonide 9 was synthesized, through heptose intermediate 5, starting with D-glyceraldehyde acetonide (1).The key steps were two consecutive four-carbon homologations, each consisting of four reactions: (i) stereoselective elongation of the aldehyde precursor with 2-(trimethylsiloxy)furan, giving Cn+4 butenolide templates 2 and 6, (ii) anti-selective cis-dihydroxylation of the butenolide double bond, giving fully functionalized lactones 3 and 7, (iii) lactone ring opening and protection, giving open-chain methyl esters 4 and 8, and (iv) DIBAL reduction to aldoses 5 and 9.At the end of the eight-step sequence, undecose 9 was prepared in a 5.1percent overall yield, which corresponded to a 69.5percent average yield per step.