Duplicated ring enlargement of 4,9-methanothia[11]annulene to 6,11-methanothia[15]annulene

作者：Kuroda Shigeyasu^*; Kasai Rie; Nagaya Ryo; Miyatake Ryuta; Horino Yoshikazu; Matsumoto Naoko; Oda Mitsunori

来源：Tetrahedron Letters, 2011, 52(13): 1426-1429.

DOI：10.1016/j.tetlet.2010.11.072

• Methanothia-annulene
• X-ray crystallographic analysis
• Cycloaddition
• Electrocyclic reaction
• Enamine

3,10-Dipyrrolidinyl-4,9-methanothia[11]annulene reacts with excess dimethyl acetylenedicarboxylate (DMAD) in refluxing toluene to give ring-enlarged 6,11-methanothia[15]annulene. X-ray crystallographic analysis of the product shows two different cis,trans-dienyl parts in the ring system. Product formation possibly involves pi-facial selective addition of the enamine with DMAD and torque-selective ring opening of the intermediate cyclobutenes.

• 出版日期2011-3-30