Occurrence of ligand coupling in the reaction of the 2-thienyl sulfoxides with organometallic compounds

✍ Scribed by Shigeru Oae; Yoichi Inubushi; Masakuni Yoshihara

• Publisher: John Wiley and Sons
• Year: 1993
• Tongue: English
• Weight: 380 KB
• Volume: 4
• Category: Article
• ISSN: 1042-7163
• DOI: 10.1002/hc.520040211

✦ Synopsis

Treatment of 2-p.yridyl 2-thienyl sulfoxide with 2thienyllithium was found to give both 2-(2-pyri-dy1)thiophene 2 and 2,5-(di-2-pyridyl)thiophene 3. The reaction between 2-thienyllithium and thionyl chloride was found to give 2,2'-bithienyl 8, a coupling product, which is also formed by the reaction between di-2-thienyi sulfoxide 7 and 2-thienyllithium.

INTROD UCTI0.N

Although much more work remains to be done on ligand coupling within sulfurane intermediates, the concept has been introduced [l], and numerous studies of ligand coupling reactions have been carried out [2]. From an early period, the occurrence of the coupling seems to be associated with the electronic state of the coupling carbon atom of the coupling ligands, while the electronic state of the carbon ligands is considered to be diagnosed roughly on the basis of I3C NMR chemical shifts. Indeed, this working hypothesis has led to many interesting findings. The sulfoxides which can undergo ligand coupling on treatment with benzyl, vinyl, or similar organometallic reagents carry an aromatic group whose a-carbon chemical shift Dedicated to Prof. James Cullen Martin on the occasion of his *To whom correspondence should be addressed. sixty-fifth birthday.