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Most Requested Journal Articles 2002-Chemistry and Related

Following is one of the documents most requested by researchers using CAS electronic products.

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 Science
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 5/4/2007 9:16:22 AM