Facile generation and trapping of .alpha.-oxo-o-quinodimethanes: synthesis of 3-aryl-3,4-dihydroisocoumarins and protoberberines
摘要:
Fluorodesilylation of o-((trimethylsilyl)methyl)benzoyl derivatives 5 in the presence of aromatic aldehydes and alkyl fumarates gives 3-aryl-3,4-dihydroisocoumarins 6 and alpha-tetralones 10, respectively. Reaction of 5 with 3,4-dihydroisoquinolinium salts 19 leads to 8-oxoberbines 21. Using this procedure, racemic hydrangenol, phyllodulcin, tetrahydropalmatine (22a), and canadine (22b) have been synthesized.
Thermal addition reactions to benzocyclobutenones studied by flash photolysis
作者:P. Schiess、M. Eberle、M. Huys-Francotte、J. Wirz
DOI:10.1016/s0040-4039(01)80210-0
日期:1984.1
Ortho-quinoid vinylketenes 2 have been generated through flashphotolysis of benzocyclobutenones 1. A kinetic study of intermolecular addition reactions of 2 competing with the recyclization 2 → 1 reveals strikingly different substituent effects for the addition of methanol and of dienophiles.