A Straightforward Procedure for the [2+2+2] Cycloaddition of Enediynes

作者：Geny Anais; Gaudrel Sophie; Slowinski Franck; Amatore Muriel; Chouraqui Gaelle; Malacria Max; Aubert Corinne^*; Gandon Vincent

来源：Advanced Synthesis & Catalysis, 2009, 351(1-2): 271-275.

DOI：10.1002/adsc.200800646

• cobalt
• cycloaddition
• dienes
• manganese
• N-heterocyclic carbenes
• polycycles

Enediynes undergo intramolecular [2 + 2 + 2] cycloaddition in the presence of cobalt(II) iodide (CoI2), manganese and an N-heterocyclic carbene (IPr) generated in situ from the corresponding imidazolium salt and butyllithium (BuLi). Polycyclic cyclohexadienes are obtained selectively. This new method represents an interesting alternative to those employing air-sensitive cyclopentadienylcobalt [CpCoL2 (L=CO, C2H4)] catalysts. Moreover, the N-heterocyclic carbene can be used catalytically, which is a significant improvement compared to the corresponding phosphine-based system which requires an excess of ligand.

• 出版日期2009-1