Transition metal aromatic ring construction

T. Matsuda, Synthesis of heterocycles via X—H bond addition to diynes. in Transition-Metal-Mediated Aromatic Ring Construction. (Ed K. Tanaka), p. 537. John Wiley Sons, Ltd., New York, 2013. 

TRANSITION METAL-MEDIATED AROMATIC RING CONSTRUCTION... 

Recent significant advance in the area of the transition metal-mediated aromatic ring construction reactions enables the construction of substituted benzenoid aromatic rings with efficient and convenient manners [1], These aromatic ring constrnction reactions provide promising new routes to the complex benzenoid aromatic compounds. In this chapter, I snmmarize the intermolecular multicomponent reactions and the intramolecnlar single-component reactions, which are able to construct benzenoid aromatic rings. 

In this chapter, the intermolecular multicomponent aromatic ring construction reactions and intramolecular single-component aromatic ring construction reactions are described. Among them, the [2+2+2] cycloaddition and intramolecular hydroarylation reactions are the most widely employed and reliable method. Various polycyclic and sterically hindered aromatic compounds have been synthesized by this method. In the past 10 years, the asymmetric [2+2+2] cycloaddition and intramolecular hydroarylation reactions have been developed, which enabled the enantioselec-tive synthesis of sterically hindered chiral aromatic compounds, such as axially chiral biaryls, planar chiral cyclophanes, and helically chiral heUcenes. Details of the transition metal-mediated aromatic ring construction reactions are comprehensively covered in the recently published book... 

Further development of efficient and powerful transition metal-mediated aromatic ring construction reactions would enable the more fadle and diverse synthesis of complex benzenoid aromatic compounds. 

For selected recent reviews, see (a) Hilt, G., Punner, F. (2013) Diels-Alder reactions. In Tanaka, K. (Ed.) Transition-Metal-Mediated Aromatic Ring Construction. John Wiley Sons, Hoboken, pp. 341-353. (b) Reymond, S., Cossy, J. (2008). Copper-catalyzed Diels-Alder reactions. Chemical Reviews, 108, 5359-5406. (c) Shen, J., Tan, C.-H. (2008). Br0nsted-acid and Brpnsted-base catalyzed Diels-Alder reactions. Organic Biomolecular Chemistry, 6, 3229-3236. 

Transition-Metal-Mediated Aromatic Ring Construction... 

Transition-Metal-Mediated Aromatic Ring Construction, First Edition. Edited by Ken Tanaka. 2013 John Wiley Sons, Inc. Published 2013 by John Wiley Sons, Inc. 

The transition-metal-mediated aromatic ring construction reaction via the [2 -I- 2 -I- 2] cycloaddition reaction is not restricted to the formation of a single benzene moiety. As already discussed within the intramolecular version of this reaction [i.e., the syntheses of (+)-viridin (47) and the angucyclines 58-60], this pivotal cycloaddition reaction can be used for the synthesis of naphthalene or anthracene moieties whenever it is embedded in a sequence of consecutive reactions. However, a more straightforward entry to the naphthalene core was realized during synthesis of the lignans taiwanin C (100) and E (101) (Scheme 7.21) [30]. 

Axially chiral biaryls are found widely in the key structure of useful chiral ligands and catalysts [1] and biologically active compounds [2], The conventional method for their catalytic asymmetric synthesis is based on an asymmetric cross-coupling approach [3], As a conceptually new approach to axially chiral biaryls, asymmetric aromatic ring construction via transition-metal-catalyzed [2 - - 2 + 2] cycloaddition has recently appeared [4], In 1999, Sato et al. reported two types of nickel-catalyzed [2-1-2-1-2] cycloaddition for the synthesis of functionalized biaryls [5], One was the cycloaddition of aryl-substituted monoyne 1 with acetylene, leading to biaryl 2 (Scheme 9.1), and the other was the cycloaddition of aryl-substituted 1,6-diyne 3 with acetylene, leading to biaryl 4 (Scheme 9.2) [5],... 

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