Synthesis and Photochemistry of Styryl Substituted Annelated Furan Derivatives. IV. Concentration Directed Intra- and/or Intermolecular [2+2] Cycloaddition

摘要

New cyclobutane derivatives have been synthesized by intermolecular photochemical [2+2] ethene-ethene ?head-to-head? ( 9a,b ) and ?head-to-tail? ( 10a,b–11a,b ) as well as [2+2] ethenefuran ( 12a,b ) cycloaddition from...