- Stereoselective synthesis of new glycooxathiecinone using vic-cyclic thionocarbonate haloalkylation and ring closing metathesis as key steps
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Herein, we describe the first glycoconjugate macrocyclic thiolcarbonate namely (Z)-10(S)-[3′-O-acetyl-1′,2′-O-isopropylidene-4′-deoxy-d-erythrofuranose]-4,7,9-trihydro-10H-8-thia-1,3-oxathiecin-2-one (17a) using a strategy based on two key steps synthesis: (i) a haloalkylation of vic-diol via their cyclic thionocarbonate derivatives; (ii) a macrocyclisation using ring closing metathesis reaction. Detailed here is a newly developed extension of vic-diol halogenation via the cyclic thionocarbonate function but using a range of alkyl halides other than the customarily used MeI. For example, with 1,2-O-isopropylidene-5,6-O-thionocarbonate-d-glucose (1) and allyl bromide, the 5-allylthiolcarbonate-6-bromo-6-deoxy-d-glucose derivative 6 was obtained in good yield. The later submitted to 6-allythioetherification and ring closing metathesis (RCM) with Grubbs second generation gave stereoselectively the target oxathiecinone 17a in 75% yield for the RCM step.
- Benazza, Mohammed,Kanso, Rami,Demailly, Gilles
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- Thio-sugars. I. Radical-promoted thione-thiol rearrangement of cyclic thionocarbonates: Synthesis of 5-thioglucose
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The 5,6-O-thiocarbonyl-α-D-glucofuranose derivatives 2, when subjected to one of the following reactions, undergo a radical-promoted thione-thiol rearrangement to yield the 5-S-thiolcarbonates of gluco-configuration 8 as the major product. The reactions are, (A) thermolysis with a catalytic amount of tributyltin hydride and AIBN, (B) photolysis with hexabutyldistannane, and (C) thermolysis with dimethyl phosphonate and benzoyl peroxide. On the other hand, thermolysis of 2 with trialkylsilane (condition D) yielded olefins 13 as the major product. The 5-S-gluco product 8 was converted, in three steps, to 5-thioglucose (21) in 55% yield.
- Tsuda, Yoshisuke,Sato, Yoshiyuki,Kanemitsu, Kimihiro,Hosoi, Shinzo,Shibayama, Kenji,Nakao, Kayo,Ishikawa, Yuko
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p. 1465 - 1475
(2007/10/03)
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- TRIALKYLTIN RADICAL USED TO CATALYZE THE O,S-REARRANGEMENT OF CYCLIC THIONOCARBONATES. A NEW ENTRY TO THIO-SUGARS
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The cyclic thionocarbonates give O,S-rearrangement products, the thiolcabonates, in appreciable yields, when treated with a catalytic amount of tributyltin hydride and α,α-azobisisobutyronitrile.This reaction opens a new route to regioselective preparatio
- Tsuda, Yoshisuke,Kanemitsu, Kimihiro,Kakimoto, Kyoko,Kikuchi, Tohru
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p. 2148 - 2150
(2007/10/02)
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