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Synlett 2005(16): 2437-2440  
DOI: 10.1055/s-2005-872686
LETTER
© Georg Thieme Verlag Stuttgart · New York

Lewis Acid Mediated Reductive Ring Opening of 2-Methoxyethylidene Acetals: A New Approach to 2-Methoxyethyl (MOE) Ethers of cis-Diols

Stephen Hanessian*, Roger Machaalani
Department of Chemistry,, Université de Montréal, C. P. 6128, Succ. Centre-Ville, Montréal, PQ, H3C 3J7, Canada
Fax: +1(514)3435728; e-Mail: stephen.hanessian@umontreal.ca;
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Publication History

Received 22 June 2005
Publication Date:
21 September 2005 (online)

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Abstract

The reductive opening of 2-methoxyethylidene acetals of vicinal diols in uridine and 1,4-anhydro-d-ribitol in the presence of TiCl4 and Et3SiH was investigated. The 3′-O-(2-methoxyethyl) ether of uridine and the 2′-O-(2-methoxyethyl) ether of 1,4-an­hydro-d-ribitol were isolated and characterized. The results were rationalized based on coordination effects involving proximal substituents.

Key words

acetal - reductive opening - nucleoside - antisense

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11

We have also used a combination of ZnCl2/L-Selectride, BF3·OEt2/Et3SiH, however, no opening of the acetal was observed under these conditions.

12

Decomposition was observed when MeCN and nitromethane were used as solvent.