Reaction of 1-benzoselenopyrylium salts with grignard reagents: Formation of 2,4-disubstituted selenochromenes and their conversion into the corresponding 1-benzoselenopyrylium salts

✍ Scribed by Haruki Sashida; Masahiro Yoshida; Hiroshi Minamida; Masanori Teranishi

• Publisher: Journal of Heterocyclic Chemistry
• Year: 2002
• Tongue: English
• Weight: 98 KB
• Volume: 39
• Category: Article
• ISSN: 0022-152X
• DOI: 10.1002/jhet.5570390226

✦ Synopsis

Abstract

Treatment of 2‐tert‐butyl‐1‐benzoselenopyrylium salts 1A and 2‐phenyl‐1‐benzoselenopyrylium salts 1B with an alkyl(phenyl)magnesium halide resulted in nucleophilic addition at the C‐4 position to give the corresponding 2,4‐disubstituted 4__H__‐selenochromenes 2A and 2B in good yields, respectively. The obtained selenochromenes 2 were then easily converted into the 4‐substituted 2‐tert‐butyl‐1‐benzoselenopyrylium salts 6A by treatment with triphenylcarbenium tetrafluoroborate in high yields. The 4‐substituted 2‐phenyl derivatives 6B were also obtained in a similar manner. The reaction of the unsubstituted 1‐benzoselenopy‐rylium salt 1C with an alkylmagnesium halide is also described.