研究室工作进展 Mar. 16th, 2013.

 Construction of Octa-alkyl Substituted and Deca-substituted All-cis Octatetraenes via Linear Dimerization of 1,4-Dicopper-1,3-butadienes and Subsequent Cross-coupling with Halides 

Junnian Wei, Zitao Wang, Wen-Xiong Zhang, and Zhenfeng Xi*

Org. Lett. 2013, 15, 1222-1225.

 All-cis substituted conjugated polyenes are important, but no efficient synthetic method is available. This work reports an efficient synthesis of octa-alkyl substituted and deca-substituted all-cis octatetraenes, via LiI-assiated thermal decomposition-linear dimerization of 1,4-dicopper-1,3-butadienes and subsequent Pd-catalyzed cross-coupling between C-Cu bonds and electrophiles.

This research group has been working, for 15 years, on the synthesis and synthetic applications of multiply substituted 1-lithio 1,3-butadienes and 1,4-dilithio 1,3-butadienes(see for reviews: Acc. Chem. Res. 2010, 43, 1342-1351; Pure and Applied Chemistry 2009, 81, 235-246; Bull. Chem. Soc. Jpn. 2007, 80, 1021-1036; Eur. J. Org. Chem. 2004, 2773-2781). The alkyl substituents on the butadienyl skeletons are all-cis oriented. The addition of lithium iodide was found in this work very effective for the thermal decomposition-linear dimerization of alkenylcopper compounds.