B. Venugopalan et al., ROLE OF RADICAL-INITIATED CYCLIZATION REACTIONS IN THE SYNTHESIS OF ARTEMISININ BASED NOVEL RING SKELETONS, Tetrahedron letters, 34(39), 1993, pp. 6305-6308
Refluxing the propargyl ether 2c with nBu3SnH/AIBN in toluene gave the
clean single stereoisomer 3. Similarly the other isomer 2d underwent
a smooth radical cyclisation to give 5. The allyl ether 2e gave 6, a 1
,2-cis 1,5-trans product, under similar condition whereas the ether 2f
gave two products, namely, Compound 7 (1,2-cis 1,5-cis) and Compound
8 (1,2-cis 1,5-trans).