Tandem double intramolecular [4+2]/[3+2] cycloadditions of nitroalkenes. The fused/bridged mode
Scott E Denmark1, Laurent Gomez
1Roger Adams Laboratory, Department of Chemistry, University of Illinois, Urbana, Illinois 61801, USA. denmark@scs.uiuc.edu
Abstract:
A new class of tandem [4+2]/[3+2] cycloadditions of nitroalkenes is described in which both pericyclic processes are intramolecular. Two subclasses of intra [4+2]/intra [3+2] cycloadditions have been explored in which the dipolarophile is tethered at either C(5) or C(6) of the nitronate. For both families of precursors, the cycloadditions occur in good yield and are found to be highly regio- and stereoselective. This method converts linear polyenes to functionalized polycyclic systems bearing up to six stereogenic centers.
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