Regioselective Protection of Sugars Catalyzed by Dimethyltin Dichloride

Abstract

The first catalytic process for protection of hydroxyl groups in sugars has been developed. Highly regioselective protection was accomplished along with high chemical yield. The regioselectivity of the benzoylation was realized as an intrinsic character of sugars based on a stereorelationship among their hydroxyl groups. Furthermore, complete protection of alpha-methyl glucoside and beta-methyl xyloside was accomplished.

Auf dem Weg zur automatisierten Oligosaccharid‐ Synthese

“…Dazu gehçren z. B. die organokatalytische 4-O-Acylierung von n-Octyl-b-d-glucopyranosid, [8] die Me 2 SnCl 2 -katalysierte regioselektive Benzoylierung von Methyl-a-d-glucopyranosid, [9] die Iridium-katalysierte regioselektive Trisilylierung von Methyl-a-glycosiden, [10] die selektive Tandem-Chlorierung/O-Formylierung von Zuckern mit dem Vilsmeier-Reagens [11] und die TandemAcetalisierung/Acetylierung von Zuckern zur simultanen Einführung von Isopropyliden-und Acetylgruppen unter lç-sungsmittelfreien Bedingungen. [12] Abbildung 1.…”

Regioselective Benzoylation of Glycopyranosides by Benzoyl Chloride in the Presence of MoO2(acac)2

“…Primary hydroxyl groups of sugars demonstrated high reactivity. [1] Tin organic compounds [2][3][4][5][6][7][8][9][10][11] ; cuprum, [12][13][14] mercury, [12] and nickel [15] chelates; certain amines [16,17] ; BOP-Cl [18] ; Le BOP [19] ; Lewis acids [20][21][22] ; silver(I) oxide [23,24] ; phase-transfer catalysis [25] ; Mitsunobu reaction [26] ; and organocatalysis [27,28] are used for regioselective acylation of carbohydrates. Good results are accomplished in certain occasions, but regioselective acylation still is a challenge.…”

Chiral Benzazaborole‐Catalyzed Regioselective Sulfonylation of Unprotected Carbohydrate Derivatives

“…reported the organotin-catalyzed regioselective acylation through tin alkoxide formation (Scheme 1b). [7] Although organotin catalysts are widely used, their inherentp otential toxicity poses ap roblem sometimes. [8] Recently,Dong et al reported the iron-catalyzed alkylation of polyols, thusa voiding the use of tin-based catalysts (Scheme 1c).…”