Anciaux AJ,
Demonceau A,
Noels AF *,
Hubert AJ *,
Warin R,
Teyssié P.
University of Liège, Belgium
Transition-Metal-Catalyzed Reactions of Diazo Compounds. 2. Addition to Aromatic Molecules:
Catalysis of Buchner’s Synthesis of Cycloheptatrienes.
J. Org. Chem. 1981;
46: 873-876
DOI:
10.1021/jo00318a010
Keywords
Buchner reaction - carbenes - carbenoids - cycloheptatrienes - diazo compounds - rhodium
catalysis - ring expansion
Significance
Discovered in 1885, the Buchner reaction transforms arenes into cycloheptatrienes
(Ber.
Dtsch. Chem. Ges. 1885, 18, 2377–2379). In the seminal work, a
carbene is generated in situ at high temperature or under light irradiation, and
then undergoes insertion into an arene to form a norcaradiene. Reversible 6π
disrotatory electrocyclic ring opening and [1,5]-hydride migration then leads to a
complex isomeric mixture of ‘Buchner esters’. The transition-metal-catalyzed
variant, first reported by Noels, Hubert and co-workers in 1981, allows for much
milder reaction conditions to generate a metal carbenoid species and usually yields
the kinetic non-conjugated cycloheptatrienyl ester as one main regioisomer.
Comment
While rhodium(II) complexes are typically used, silver(I), copper(II) and iron(III)
have also been reported as efficient catalysts for this transformation. Intramolecular
variants have proven to be extremely useful and regioselective, and have been applied
in several total syntheses.1 More recently, the scope of carbene source has been extended to alkynes as a less
dangerous alternative to diazo compounds and also includes asymmetric variants.2
Reviews: (1) S. E. Reisman, R. R. Nani, S. Levin Synlett
2011, 17, 2437–2442. (2) G. Ma, K.-F. Wei, M. Song, Y.-L. Dang, Y. Yue, B. Han, H. Su, W.-B.
Shen Org. Biomol. Chem.
2023, 21, 5150–5157.
