Tandem Inter [4 + 2]/Intra [3 + 2] Cycloadditions of Nitroalkenes. The Bridged Mode (beta-Tether).
A new variation of the tandem inter [4 + 2]/intra [3 + 2] cycloaddition of nitroalkenes has been developed. This method involves the Lewis acid-promoted [4 + 2] cycloaddition of nitro olefins 12 with 1-alkoxy-1,4-dienes 3. The resulting nitronates 13, bearing a C(5) tethered dipolarophile, undergo thermal, intramolecular [3 + 2] cycloaddition to afford stable tricyclic nitroso acetals 14, which can be subsequently reduced to unveil a new carbocycle 16. Thus, in three steps, highly functionalized aminocyclopentanes can be stereoselectively constructed in high yield.
Denmark
Scott E.
SE
Roger Adams Laboratory, Department of Chemistry, University of Illinois Urbana, Illinois 61801.
Dixon
Julie A.
JA