Authors: Jeremy P. Olson and Huw M. L. Davies
Org. Lett.,
2008, 10 (4), 573–576
The reaction of benzofuranyldiazoacetates with 1,3-dienes catalyzed by the dirhodium tetracarboxylate Rh2(R-DOSP)4, generates formal [4 + 3] cycloadducts with >94% de and 91−98% ee. The reaction proceeds by a tandem cyclopropanation/Cope rearrangement followed by a stereoselective tautomerization. This methodology was extended to a formal synthesis of (+)-frondosin B.