Domino Cyclization of 1,n-Enynes (n = 7, 8, 9) Giving Derivatives of Pyrane, Chromene, Fluorene, Phenanthrene and Dibenzo[7]annulene by Ruthenium Complexes

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• 作者：Hao-Wei Ma ; Pei-Min Chen ; Ji-Xian Lo ; Ying-Chih Lin ; Shou-Ling Huang ; Chi-Ren Chen ; Pi-Yeh Chia
• 刊名：Journal of Organic Chemistry
• 出版年：2016
• 出版时间：June 3, 2016
• 年：2016
• 卷：81
• 期：11
• 页码：4494-4505
• 全文大小：534K
• 年卷期：0
• ISSN：1520-6904

文摘

Cyclization of the ether enyne 1 catalyzed by [Ru]NCCH₃⁺ ([Ru] = Cp(PPh₃)₂Ru) in CHCl₃ generates a diastereomeric mixture of the substituted tetrahydropyran 11. Presumably, formation of an allenylidene complex is followed by a cyclization by nucleophilic addition of the olefinic group to Cγ of the ligand giving a boat-like six-membered ring. The diastereoselectivity is controlled by the 1,3-diaxial interaction. The vinylidene complex 7, a precursor of 11, is obtained from 1 and [Ru]Cl. In a mixture of MeOH/CHCl₃, the domino cyclization of 1 further affords 14a, a chromene product catalytically. The second cyclization proceeds via nucleophilic addition of the resulting olefinic unit to Cα of 7. But the ether enyne 3 with a cyclopentyl ring on the olefinic unit undergoes only single cyclization due to steric effect. The propargyl alcohol and the two terminal methyl groups on the olefinic unit shape the cyclization. Thus, similar all-carbon 1,n-enynes (n = 7, 8, 9) 4–6 each with an aromatic linker undergo direct domino cyclization catalyzed by [Ru]NCCH₃⁺, to give derivatives of tricyclic fluorene, phenanthrene and dibenzo[7]annulene, respectively, with no intermediate observed.