Serendipitous One-Step Synthesis of Cyclopentene Derivatives from 5′-Deoxy-5′-heteroarylsulfonylnucleosides as Nucleoside-Derived Julia–Kocienski Reagents

A serendipitous one-step transformation
of 5′-deoxy-5′-heteroarylsulfonylnucleosides
into cyclopentene derivatives is reported. This unique transformation
likely proceeds via a domino reaction initiated by α-deprotonation
of the heteroaryl sulfone and subsequent elimination reaction to generate
a nucleobase and an α,β-unsaturated sulfone that contains
a formyl group. The Michael addition of the nucleobase to the α,β-unsaturated
sulfone and the subsequent intramolecular Julia–Kocienski reaction
eventually generate the cyclopentene ring. Heteroarylthio and acylthio
groups can be incorporated into the cyclopentene core in place of
the nucleobase by conducting this reaction in the presence of a heteroarylthiol
and a thiocarboxylic acid, respectively. cis,cis-Trisubstituted cyclopentene derivatives are obtained
as a single stereoisomer from ribonucleoside-derived Julia–Kocienski
sulfones.