Kezuka Satoko, Tanaka Shigeru, Ohe Toshihito, Nakaya Yoshihiko, Takeuchi Ryo
Department of Chemistry and Biological Science, Aoyama Gakuin University, 5-10-1 Fuchinobe, Sagamihara 229-8558, Japan.
J Org Chem. 2006 Jan 20;71(2):543-52. doi: 10.1021/jo051874c.
[reaction: see text] [Ir(cod)Cl]2/DPPE was found to be a new catalyst for the cycloaddition of alpha,omega-diynes with monoynes to give polysubstituted benzene derivatives in high yields. Internal monoynes as well as terminal monoynes could be used. The reaction tolerates a broad range of functional groups such as alcohol, amine, alkene, ether, halogen, and nitrile. The reaction of 1,6-octadiyne derivatives with 1-alkynes gives ortho products and meta products. The regioselectivity could be controlled by the choice of ligand. The reaction with DPPE was meta selective, with meta selectivity of up to 82%. The reaction with DPPF was ortho selective, with ortho selectivity of up to 88%. We propose a mechanism to account for this regioselective cycloaddition. Ir(cod)Cl/DPPE also catalyzed the cycloaddition of alpha,omega-diynes with 2,5-dihydrofuran to give bicyclic cyclohexadiene derivatives. The reaction with 2,3-dihydrofuran and n-butyl vinyl ether gave benzene derivatives instead of cyclohexadiene derivatives. We also propose a mechanism to account for this novel aromatization that includes cleavage of the C-O bond.
[反应：见正文] 发现[Ir(cod)Cl]2/DPPE是一种新型催化剂，可使α,ω-二炔与单炔进行环加成反应，以高产率生成多取代苯衍生物。内单炔和端单炔均可使用。该反应能耐受多种官能团，如醇、胺、烯烃、醚、卤素和腈。1,6-辛二炔衍生物与1-炔烃的反应生成邻位产物和间位产物。区域选择性可通过配体的选择来控制。与DPPE的反应具有间位选择性，间位选择性高达82%。与DPPF的反应具有邻位选择性，邻位选择性高达88%。我们提出了一种机制来解释这种区域选择性环加成反应。[Ir(cod)Cl]2/DPPE还催化α,ω-二炔与2,5-二氢呋喃的环加成反应，生成双环环己二烯衍生物。与2,3-二氢呋喃和正丁基乙烯基醚的反应生成苯衍生物而非环己二烯衍生物。我们还提出了一种机制来解释这种包括C-O键断裂的新型芳构化反应。
