Gold(I)-Catalyzed Intramolecular Cyclopropanation of Dienynes

• Published in: Chemistry : a European journal Vol. 12; no. 6; pp. 1694 - 1702
• Main Authors: Nieto-Oberhuber, Cristina, López, Salomé, Muñoz, M. Paz, Jiménez-Núñez, Eloísa, Buñuel, Elena, Cárdenas, Diego J., Echavarren, Antonio M.
• Format: Journal Article
• Language: English
• Published: Weinheim WILEY-VCH Verlag 08.02.2006; WILEY‐VCH Verlag; Wiley
• Subjects: alkynes; Chemistry; Chemistry, Multidisciplinary; cyclization; density functional calculations; gold; Physical Sciences; platinum; Science & Technology; zinc; SKELETAL REORGANIZATION; MOLECULAR CALCULATIONS; SESQUITERPENE ALCOHOL; MECHANISM; EFFECTIVE CORE POTENTIALS; alkynes; cyclization; CATALYZED CYCLOISOMERIZATION REACTIONS; gold; density functional calculations; platinum; ENYNE METATHESIS; X-RAY CRYSTAL; zinc
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.200501089

Gold(I) complexes are the most active catalysts for the biscyclopropanation of dienynes to form tetracyclic compounds. PtII and ZnII are also able to promote the biscyclopropanation, although less efficiently. The configurations obtained in all cases with the use of gold(I) catalysts can be explained by the pathway proceeding through anti cyclopropyl gold carbenes. Similar intermediates are most probably involved in reactions catalyzed by RuII and PtII. Two different cyclopropanation pathways have been found; they depend on the structures of the cyclopropyl gold carbenes (anti or syn) and the relative arrangements of the metal carbenes and the alkenes. Gold(I) complexes are the most active catalysts for the biscyclopropanation of dienynes to form tetracyclic compounds (see scheme): The configurations of these tetracycles can be explained by the pathway proceeding through cyclopropanation of the intermediate gold carbenes with the pendant alkene.