Regioselectivity in Alkylation Reactions of 1,2‐O‐Stannylene Acetals of d‐Arabinofuranose

Abstract

The synthesis of β‐arabinofuranosides via alkylation of 1,2‐O‐stannylene acetal intermediates has been studied. With reactive alkyl halides (benzyl bromide, allyl bromide, and p‐methoxybenzyl chloride), the method provides a mixture of β‐arabinofuranosides and 2‐O‐alkylated lactols in ratios of 4:1 to 1:1.5. However, with carbohydrate‐derived electrophiles, no alkylated products are produced. It appears, therefore, that the method is limited to the preparation of β‐arabinofuranosides of simple alcohols. Through the use of computational chemistry, we have explored the conformational properties of one of these stannylene acetals and propose that these species exist in more than one conformation in solution and that this contributes to the relatively poor regioselectivity in these reactions.

Keywords:

• Stannylene acetal
• β‐arabinofuranosides
• Glycosylation
• Alkylation

Acknowledgments

This work was supported by The National Institutes of Health and the Ohio Supercomputer Center. OSD thanks the Ohio State University College of Arts and Science for a senior Honors Thesis Scholarship.