No abstract

A hetero-Diels-Alder reaction of vinyl sulfoxides with o-quinone methides precursor constructs highly functionalized [5,6] aromatic spiroketal skeletons in moderate to good yields with high regioselectivity. The two functional groups (ketone and olefin) can be further subjected to many synthetic transformations.

An Efficient Synthesis of Highly Functionalized [5,6] Aromatic Spiroketals by Hetero-Diels-Alder Reaction. -Thermal hetero-Diels-Alder reaction of vinyl sulfoxides (I) with o-quinone methide precursors (II) provides an effective access towards [5,6]-spiroketals (III), widely occurring among natural products. The sulfoxide group on the dienophile perfectly controls the regioselectivity. -(ZHOU, G.; ZHU, J.; XIE*, Z.; LI, Y.; Org. Lett. 10 (2008) 5, 721-724; State Key Lab. Appl. Org.

Expeditious Synthesis of the Aromatic Spiroketal Skeleton Using Hetero--Diels-Alder Cycloaddition. -The method allows the rapid synthesis of [6,6] aromatic spiroketal skeletons, present in various antibiotics. -(ZHOU, G.; ZHENG, D.; DA, S.; XIE*, Z.; LI, Y.; Tetrahedron Lett. 47 (2006) 20, 3349-3352; State Key Lab.