AsymmetricPrinscyclization of in situ generated quinone methides and o-aminobenzaldehyde has been developed with chiral phosphoric acid as an efficient catalyst. This unconventional method provides a facile access to diverse functionalized trans-fused pyrano-/furo-tetrahydroquinoline derivatives in excellent yield and with excellent diastereo- and enantioselectivities (up to 99% yield and 99% ee)
A facile synthesis of aryldihydropyrans using a Sonogashira–selenoetherification strategy
作者:Margaret A Brimble、Gabrielle S Pavia、Ralph J Stevenson
DOI:10.1016/s0040-4039(02)00065-5
日期:2002.2
with a range of phenyl and naphthyl bromides affords the appropriate aryl acetylenic alcohols which then undergo ready reduction to the corresponding (E)-1-aryl-5-hydroxyalkenes. Subsequent selenoetherification of the (E)-5-hydroxyalkenes proceeds via a 6-endo-trig pathway cleanly affording the trans-2-aryl-3-phenylselenyltetrahydropyrans. Finally oxidativeelimination of the selenides afforded the 2-aryl-2