Highly Regio- and Stereoselective Cycloreductions of 1,6- and 1,7-Enynes Activated with a Carbonyl Functionality

✍ Scribed by Chang Ho Oh; Hyung Hoon Jung; Joo Sung Kim; Seung Woo Cho

• Publisher: John Wiley and Sons
• Year: 2000
• Tongue: English
• Weight: 119 KB
• Volume: 112
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/(sici)1521-3757(20000218)112:4<768::aid-ange768>3.0.co;2-k

✦ Synopsis

The cyclization of enynes or halodienes has been widely utilized in the synthesis of structurally complex natural and synthetic products. [1] Various 1,6-and 1,7-enynes, aided by suitable palladium catalysts, cycloisomerize to the corresponding dienes, [2] which could further serve as valuable water (15 mL) and ice (40 g) was added, and the reaction mixture was stirred for a further 2 h during which time a black, oily solid separated out. The solution was removed by decantation, and the oily solid was dried in a vacuum desiccator. The dry residue was redissolved in dichloromethane (1 mL), placed on a silica gel column (2.5 cm  1.5 cm), and eluted with dichloromethane. The fast-moving purple band was collected, ethanol was added, and the dichloromethane was removed under reduced pressure to yield green crystals. Recrystallization from dichloromethane/ethanol yielded pure 2 as purple crystals (12 mg, 5 %). 1