Regio- and Enantioselective Epoxidation of Dienes by a Chiral Dioxirane: Synthesis of Optically Active Vinyl cis-Epoxides

✍ Scribed by Christopher P. Burke; Yian Shi

• Publisher: John Wiley and Sons
• Year: 2006
• Tongue: English
• Weight: 116 KB
• Volume: 118
• Category: Article
• ISSN: 0044-8249
• DOI: 10.1002/ange.200600840

✦ Synopsis

Optically active vinyl epoxides are very useful synthetic intermediates, [1] and enantioselective monoepoxidation of conjugated dienes presents an efficient approach to these compounds. [2, 3] Enantioselective epoxidation of conjugated dienes using chiral (salen)Mn catalysts has been shown to proceed predominantly at the cis-olefin with high regioselectivity and high enantioselectivity. [3] In the case of acyclic dienes, the epoxidation gave optically active vinyl transepoxides as major products. [3a,b,d] Earlier, we reported that fructose-derived ketone 1 (Scheme 1) is effective for the regioselective epoxidation of conjugated dienes to provide vinyl trans-and trisubstituted epoxides with high ee values [Eq. ( 1)]. [4, 5] Nevertheless, an efficient synthesis of chiral vinyl cis-epoxides is still highly desirable.