Stereodefined Tandem Addition Reactions of 2-Arenes: A Versatile Route to Functionalized Cyclohexenes
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- 作者：Michael E. Kopach ; Stanley P. Kolis ; Ronggang Liu ; Jason W. Robertson ; Mahendra D. Chordia ; and W. Dean Harman
- 刊名：Journal of the American Chemical Society
- 出版年：1998
- 出版时间：July 1, 1998
- 年：1998
- 卷：120
- 期：25
- 页码：6199 - 6204
- 全文大小：298K
- 年卷期：v.120,no.25(July 1, 1998)
- ISSN：1520-5126
文摘
A series of anisoles are complexed by pentaammineosmium(II),and the resulting 5,6-
2-anisolecomplexes are treated with activated olefins or acetals in the presenceof triflic acid to form 4H-anisoliumcomplexes. These intermediates are capable of undergoing inter- orintramolecular nucleophilic additionreactions at C3, and 2-methoxy-1,3-cyclohexadiene complexes are formed.These complexes are readilyconverted into functionalized cyclohexenones, cyclohexadienes, andcyclohexenes. When BF3·OEt2 isused,it is possible to form a 4H-anisolium complex with a pendentboron enolate, which can ultimately undergointramolecular addition to C1 to form the corresponding [4 + 2]cycloadduct. For cases in which an activatedalkyne is added to a C4-alkylated anisole, a migration of the vinylgroup occurs, leading to 4-methyl-3-vinylanisoles.
2-anisolecomplexes are treated with activated olefins or acetals in the presenceof triflic acid to form 4H-anisoliumcomplexes. These intermediates are capable of undergoing inter- orintramolecular nucleophilic additionreactions at C3, and 2-methoxy-1,3-cyclohexadiene complexes are formed.These complexes are readilyconverted into functionalized cyclohexenones, cyclohexadienes, andcyclohexenes. When BF3·OEt2 isused,it is possible to form a 4H-anisolium complex with a pendentboron enolate, which can ultimately undergointramolecular addition to C1 to form the corresponding [4 + 2]cycloadduct. For cases in which an activatedalkyne is added to a C4-alkylated anisole, a migration of the vinylgroup occurs, leading to 4-methyl-3-vinylanisoles.