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CAS indexed 45 chemical substances from this document.
CAS subject entries for this document include: Glycosidation; Ring closure and formation.

TITLE:	Glucan synthesis. Part VI. Total synthesis of cyclomaltohexaose
AUTHOR(S):	Takahashi, Yukio; Ogawa, Tomoya
CORPORATE SOURCE:	Inst. Phys. Chem. Res., Wako, 351-01, Japan
SOURCE:	Carbohydrate Research (1987), 164, 277-96 CODEN: CRBRAT; ISSN: 0008-6215
PUBLISHER:	Elsevier
LANGUAGE:	English

ABSTRACT:
Described for the first time is a total synthesis of cyclomaltohexaose (I), in 0.3% overall yield, in 21 steps starting from maltose. Maltose was transformed into allyl O-(2,3,6-tri-O-benzyl-.alpha.-D-glucopyranosyl)-(1.fwdarw.4)-2,3,6-tri-O-ben zyl-.beta.-D-glucopyranoside (II) and O-(4-O-acetyl-2,3,6-tri-O-benzyl-.alpha.-D-glucopyranosyl)-(1.fwdarw.4)-2,3, 6-tri-O-benzyl-.beta.-D-glucopyranosyl fluoride (III). Glycosylation of II with III and partial deprotection of the product gave allyl O-(2,3,6-tri-O-benzyl-.alpha.-D-glucopyrabosyl)-(1.fwdarw.4)-bis[O-(2,3,6-tr i-O-benzyl-.alpha.-D-glucopyranosyl)-(1.fwdarw.4)]-2,3,6-tri-O-benzyl-.beta. -D-glucopyranoside, which was further glycosylated with III, and converted into the key intermediate O-(2,3,6-tri-O-benzyl-.alpha.-D-glucopyranosyl)-(1.fwdarw.4)-tetrakis[O-(2,3 ,6-tri-O-benzyl-.alpha.-D-glucopyranosyl)-(1.fwdarw.4)]-2,3,6-tri-O-benzyl-. beta.-D-glucopyranosyl fluoride (IV). The crucial cyclization was achieved through intramol. glycosylation of the key intermediate IV, to afford a 21% yield of octadeca-O-benzylcyclomaltohexaose. Catalytic transfer hydrogenation yielded I.

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Updated 5/10/2007 1:21:21 PM