Studies toward the Synthesis of α-Fluorinated Phosphonates via Tin-Mediated Cleavage of α-Fluoro-α-(pyrimidin-2-ylsulfonyl)alkylphosphonates. Intramolecular Cyclization of the α-Phosphonyl Radicals
作者:Stanislaw F. Wnuk、Luis A. Bergolla、Pedro I. Garcia
DOI:10.1021/jo0111560
日期:2002.5.1
sulfone moiety and an alternative route for the preparation of alpha-fluorinated phosphonates. Desulfonylation is suggested to proceed via attack of tin radical at an oxygen (or sulfur) atom of the sulfonyl group to give a stabilized alpha-phosphonyl radical intermediate. The latter was found to undergo 5-exo-trig ring closure to give the corresponding 2-methylcyclopentylphosphonates. Treatment of diethyl
This dual catalytic regime exhibited high efficiency and good functional group compacity. A wide variety of substrates bearing a diverse set of functional groups could be converted into chiral phosphates in good to excellent yields and enantioselectivities. The utility of the method was also demonstrated by the development of a new phosphine ligand and the synthesis of enzyme inhibitor derivatives