catalyze the transfer of carbene groups: C(R)CO(2)Et (R = H, Me) from N(2)C(R)CO(2)Et to afford products that depend on the nature of the metal center. The copper-basedcatalyst yields exclusively a cycloheptatriene derivative from the Buchner reaction, whereas the gold analog affords a mixture of products derived either from the formal insertion of the carbene unit into the aromatic C-H bond or from its addition
Büchner Reactions Catalyzed by a Silver(I) Pyridylpyrrolide: Understanding Arene C═C Insertion Selectivity
作者:Nobuyuki Komine、Jaime A. Flores、Kuntal Pal、Kenneth G. Caulton、Daniel J. Mindiola
DOI:10.1021/om301240d
日期:2013.6.10
The complex Ag-3(mu(2)-3,5-(CF3)(2)PyrPy)(3) (3,5-(CF3)(2)PyrPy = 2,2'-pyridylpyrrolide(1-) ligand) catalytically promotes the insertion of the carbene of ethyl diazoacetate (EDA), at room temperature, into the C=C bond of a series of arenes to ultimately ring-open them and form the corresponding cycloheptatrienes. In one case, the norcaradiene intermediate can be isolated, while regioselective C=C insertion can be promoted with certain arene substrates. The mechanism of C=C insertion, preference over C-H insertion, and origin of C=C regioselectivity has been probed by a combination of experimental and theoretical studies.
Buchner; Hediger, Chemische Berichte, 1903, vol. 36, p. 3507
作者:Buchner、Hediger
DOI:——
日期:——
Regioselective and Enantioselective Intermolecular Buchner Ring Expansions in Flow
作者:Gabrielle S. Fleming、Aaron B. Beeler
DOI:10.1021/acs.orglett.7b02537
日期:2017.10.6
The firstexample of a regioselective and enantioselective intermolecular Buchner ring expansion is reported using continuous flow. The practicality and scope of the reaction are greatly improved under flow conditions. Reactions of ethyl diazoacetate with symmetric and nonsymmetric arenes afford cycloheptatrienes in good yield and excellent regioselectivity. The firstexample of an asymmetric intermolecular
Stepwise Mechanisms in Cyclopropylcarbene Reactions
作者:Jordan M. Cummins、Timothy A. Porter、Maitland Jones
DOI:10.1021/ja9803052
日期:1998.7.1
Decomposition of a naphtho-fused cyclopropyldiazomethane leads to benzocyclooctatetraene, 1-vinylnaphthalene, 2-vinylnaphthalene, and small amounts of benzobarrelene. Diradical intermediates are postulated.