Synthesis of spiroacetal enol ethers by oxidative activation of furan derivatives.
Activation of furan by electron transfer combines with the radical stabilizing effect of the alkynyl substituent (R = Ph, MeC[triple bond]C-) to achieve site-selective cation formation. A tethered hydroxy group acts as a probe of this site-selectivity to produce the ring system present in spirocyclic natural products found in Artemisia and Chrysanthemum species. cis-Dihydroxylation proceeds with high anti-stereoselectivity with respect to the tetrahydropyranyl ring oxygen.
Robertson
Jeremy
J
Department of Chemistry, Chemistry Research Laboratory, University of Oxford, Mansfield Road, Oxford OX1 3TA, UK. jeremy.robertson@chem.ox.ac.uk
Naud
Sébastien
S