I. Synthetic approaches to Oxetanocin A and related nucleoside. II. A synthetic approach to methylene expanded oxetanocins.

摘要

We investigated several approaches to the synthesis of the natural product Oxetanocin A. Our initial approach involved the use of a borane compound with Corey's chiral auxiliary to introduce chirality to the oxetane ring. However, the use of this chemistry led to the desired compound in very poor yields. Our second approach used the Evans oxazolidinone for the introduction of chirality to the molecule. This approach was found to not be useful since the cyclization to the oxetane afforded a small amount of desired product along with other side products. The last approach involved the use of 8phenylmenthol as the source of chirality which proceeded in high yields for the formation of the oxetane ring with the desired stereochemistry. This approach led to the synthesis of a differentially protected 2,3,4-oxetanetrimethanol from which various oxetanocins can be obtained.; We also synthesized the diacetate precursor of a methylene expanded oxetanocin analogue in a few steps from S-glycidol.