Regioselective total synthesis of (±) Neorautane, (±) Neorautanin and their analogs. Microwave mediated synthesis of 2H-chromenes from propargyl phenyl ethers

Recent Advances in Microwave-Assisted Synthesis of Heterocyclic Compounds

“…(Fig. (65)) [417]. When propargyl ether 286 was heated in xylene at 170 °C for 48 h, the 2 H -chromene 2 8 7 was obtained in 76% yield.…”

Synthesis of Pterocarpans

“…The hydroxyl protected pterocarpans (57b-k) (scheme18, Neorautane [74,75] and neorautanin [75] have been prepared by reaction of 2H-chromene 62 and o-chloromercuriphenol 63 (scheme 20).…”

Microwave-Assisted Natural Product Chemistry

“…G.K. Trivedi et al reported an approach applying the microwave-assisted cyclization of propargyl phenyl ethers [25]. Thus, heating of these starting materials to reflux (170 • C) in dry xylene resulted in the formation of the angular chromene as the sole product in good yield (76-83%).…”