Generation of oxiranyllithiums and oxiranyl Grignard reagents having a carbanion-destabilizing group from sulfinyloxiranes: Their property and an application to asymmetric synthesis of epoxides and alcohols

✍ Scribed by Tsuyoshi Satoh; Shigeko Kobayashi; Shino Nakanishi; Kyoko Horiguchi; Shiro Irisa

• Publisher: Elsevier Science
• Year: 1999
• Tongue: French
• Weight: 910 KB
• Volume: 55
• Category: Article
• ISSN: 0040-4020
• DOI: 10.1016/s0040-4020(99)00038-1

✦ Synopsis

The first generation of oxiranyllithiums and oxiranyl Grignard reagents having a carbanion-destabilizing group (alkyl group) was realized from sulfinyloxiranes via the ligand exchange reaction of sulfoxides with tert-butyllithium or ethylmagnesium chloridein THF at -80 to -100 *C. The generated oxiranyllithiums were found to be very unstable; however, these anions reacted with several electrophiles to give epoxides in up to 86% yield. The oxiranyl Grignard reagents were found to be more stable and much less reactive than the oxiranyllithiums. The reactivities of the oxiranyllithiums having several alkyi groups were investigated.

As an application of the method, optically active tri-and tetra-substituted epoxides and alcohols were synthesized from optically active chloromethyl p-tolyl sulfoxide via the oxiranyllithiums.