Protecting Group Manipulation on d‐Glucosamine Propane‐1,3‐diyl Dithioacetal

This is part 5 of a series of work on the chemistry of propane‐1,3‐diyl dithioacetals of carbohydrates; for the former parts, see references 2(c), 2(d), 2(e), 2(f), 3 in this paper.

Abstract

d‐glucosamine propane‐1,3‐diyl dithioacetal is a versatile synthetic building block, especially when being incorporated with the Corey‐Seebach method. Hence, exploring compatible protecting group patterns on this compound mainly for use with the Corey‐Seebach method is a fundamental work. Various protecting group strategies were applied. Typically, N‐protection of d‐glucosamine propane‐1,3‐diyl dithioacetal yielded N‐phthaloyl, N‐Boc, and N‐Ac derivatives. On the N‐Ac derivative, experiments differentiating 3,4‐ and 5,6‐hydroxyls by basic stable protecting groups yielded useful intermediates. Selective protections of the 6‐hydroxyl of the N‐Ac derivative were also applied. The remaining secondary hydroxyls of the resulting N‐Ac‐6‐O‐acyl d‐glucosamine propane‐1,3‐diyl dithioacetals could be methoxymethylated to tri‐O‐MOM derivatives or protected by a unique one‐pot discriminating protection to form the N‐acyl‐6‐O‐acyl‐ 3,4‐O‐methylene‐5‐O‐methoxymethyl d‐glucosamine propane‐1,3‐diyl dithioacetals as useful intermediates.

Keywords:

• d‐Glucosamine propane‐1,3‐diyl dithioacetal
• Protecting group
• Selective protection

Acknowledgments

The work was supported by the Deutsche Forschungsgemeinschaft (R.L.) and NRW Graduate School of Chemistry (Y.‐L.C.). We thank Marcus Daniel for his kind assistance during the manuscript preparation.

Notes

This is part 5 of a series of work on the chemistry of propane‐1,3‐diyl dithioacetals of carbohydrates; for the former parts, see references 2(c), 2(d), 2(e), 2(f), 3 in this paper.