A Novel Domino Reaction: Cyclization of Alkynyl Sulfides by Reaction with IPy2BF4

✍ Scribed by José Barluenga; Gustavo P. Romanelli; Lorenzo J. Alvarez-García; Isidro Llorente; José M. González; Esther García-Rodríguez; Santiago García-Granda

• Publisher: John Wiley and Sons
• Year: 1998
• Tongue: English
• Weight: 132 KB
• Volume: 37
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/(sici)1521-3773(19981204)37:22<3136::aid-anie3136>3.0.co;2-o

✦ Synopsis

Synthetic methodologies relying on transition metal chemistry have opened unusual approaches to polycyclic structures. [1, Intramolecular cyclizations of diynes mediated by organometallic complexes often take place according to an exo-exo coupling mode, whereas endo-endo and exoendo cyclizations have rarely been observed (Figure ). Described here is a novel approach to accomplish the exoendo cyclization of a,w-diynes, and preliminary studies on a related intermolecular process.

(2 mL) was added and evaporated to remove residual H 2 O. This process was repeated three times. The reaction flask was then filled with nitrogen and dry toluene (2 mL) to dissolve the initiator. e-Caprolactone (2.89 g, 25.3 mmol) was added, and the temperature was increased to 110 8C before a catalytic amount of Sn(Oct) 2 was added. The catalyst/initiator ratio was 1/400. The polymerization mixture was stirred for 24 h, diluted with THF, and poured into cold MeOH to precipitate a white crystalline powder.