Regioselective electrophilic cyclization of o-ethynylbenzyl phenyl selenides to (Z)-1-methylidene-2-phenyl-1,3-dihydro-1H-benzo[c]selenophenium salts

✍ Scribed by Haruki Sashida; Shoko Nakabayashi; Hirokazu Suzuki; Mamoru Kaname; Mao Minoura

• Book ID: 104098170
• Publisher: Elsevier Science
• Year: 2010
• Tongue: French
• Weight: 365 KB
• Volume: 51
• Category: Article
• ISSN: 0040-4039
• DOI: 10.1016/j.tetlet.2010.07.160

✦ Synopsis

o-Ethynylbenzyl phenyl selenides regioselectively reacted with trifluoromethanesulfonic acid to afford the (Z)-1-methylidene-2-phenyl-1,3-dihydro-1H-benzo[c]selenophenium salts as the major products during the 5-exo-dig mode cyclization in good yields together with minor E isomers. The structure of the major (Z)-selenophenium salt was established by the single crystal X-ray crystallographic analysis using a tert-butyl derivative.