Tandem [4 + 2]/[3 + 2] Cycloadditions: Facile and Stereoselective Construction of Polycyclic Frameworks

Scott E. Denmark, Young Choon Moon, C. B.W. Senanayake

Research output: Contribution to journalArticle

Abstract

Di- and trisubstituted nitroalkenes tethered to dipolarophiles (unsaturated esters, nitriles) undergo tandem [4 + 2]/[3 + 2] cycloadditions with 2,3-dimethyl-2-butene or butyl vinyl ether in the presence of Lewis acids. For the dimethylene tether 1, the tandem cycloadduct 4 is the direct reaction product. The E configuration of the dipolarophile is preferred, and the products arise selectively from a syn-endo pathway. For a trimethylene-tethered precursors 2 the initial [4 + 2] cycloadducts 9 are isolable and undergo the second [3 + 2]-dipolar cycloaddition upon brief warming via a syn-exo pathway. The resulting nitroso acetals (4bB/B’ and llaB/B’) are cleaved with hydrogen and Raney nickel to afford the tricyclic lactams 12 and 14 stereoselectively in good yield.

Original languageEnglish (US)
Pages (from-to)311-315
Number of pages5
JournalJournal of the American Chemical Society
Volume112
Issue number1
DOIs
StatePublished - Jan 1 1990

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ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

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