4-disubstituted furans, 5. Regiospecific mono-ipso-iodination of 3,4-bis(trimethylsilyl)furan and regiospecificipso-iodination of tris[(4-alkyl- or -aryl)furan-3-yl]boroxines to 4-substituted 3-(trimethylsilyl)furans and unsymmetrical, 3,4-disubstituted furans

✍ Scribed by Song, Zhi Zhong ;Wong, Henry N. C.

• Publisher: John Wiley and Sons
• Year: 1994
• Tongue: English
• Weight: 705 KB
• Volume: 1994
• Category: Article
• ISSN: 0947-3440
• DOI: 10.1002/jlac.199419940107

✦ Synopsis

Abstract

4‐Iodo‐3‐trimethylsilylfuran (2), obtained through the regio‐Specific iodination of 3,4‐bis(trimethylsilyl)furan (1), underwent either palladium‐ or nickel‐catalyzed cross‐coupling reactions with terminal alkenes, terminal alkynes, areneboronic acids, bis(p‐methoxycarbonylbenzyl)zinc and Grignard reagents to give 4‐substituted 3‐(trimethylsilyl)furans 3–7, which were converted into boroxines 8. Regiospecific iodination of 8 gave iodofurans 9, which afforded in the usual way unsymmetrical 3,4‐disubstituted furans 10. Boroxines 8 gave also 3,4‐disubstituted furans 11 via palladium‐catalyzed cross‐coupling reactions with piperonyl chloride and vinyl bromide. magnified image