On the selectivity of deprotection of benzyl, mpm (4-methoxybenzyl) and dmpm (3,4-dimethoxybenzyl) protecting groups for hydroxy functions

Total synthesis of (+)-A83586C, (+)-kettapeptin and (+)-azinothricin: powerful new inhibitors of β-catenin/TCF4- and E2F-mediated gene transcription

“…In the event, 24 all our fears proved groundless, for the selective deprotection of 67 proceeded very straightforwardly when 1.2 equivalents of DDQ were used for the PMB cleavage. 26 This delivered a mixture of two ringclosed hemiketal anomers and the open-chain d-hydroxy ketone, in addition to a small amount of the ring-closed glycal 68. Because of the difficulties involved in processing this mixture, we had to identify conditions that could fully convert it into 68 in good yield such that we could progress our synthesis further.…”

Synthetic Studies toward Mycobacterium tuberculosis Sulfolipid-I

“…26,43 The two DMB groups were then selectively cleaved to generate diol 21. 44 A second EDC-promoted esterification with model lipid 6 produced fully acylated 22 (Scheme 5). 27,43 Oxidative deprotection of the PMB group was followed by sulfation of the resulting alcohol with SO 3 ·pyridine to provide 24 in excellent yield.…”

A highly efficient and convergent synthesis of a hexasaccharide, a dimer of the repeating unit of the antigen O2 polysaccharide of Stenotrophomonas maltophilia

“…Triethylamine (25 mL) was added and the reaction mixture was handled as described for the preparation of 6. Flash chromatography (1:2 EtOAc-petroleum ether) of the residue gave the disaccharide 13 ( (14).-A methanolic solution [12] of HCl (1.04 N, 9 mL), prepared by adding acetyl chloride (0.8 mL) to freshly distilled MeOH (10 mL), was added to a solution of the disaccharide 13 (710 mg, 0.82 mmol) in freshly distilled MeOH (6 mL) and the solution was stirred at 48-54°C. The reaction was quenched when TLC (2:1 petroleum etherEtOAc) showed 14 (R f 0.29) was the sole product.…”