Lignans and Neolignans

Herein, we briefly outline the recent advances in the studies of stereoselectivity in the biosynthesis of norlignans, lignans, and neolignans. 

Moss GP (2000) Nomenclature of lignans and neolignans. Pure Appl Chem 72 1493-1523... 

Fig. 9C.8 Structures of lignans and neolignans isolated from a German Riesling wine...

Davin, F.B. and Lewis, N.G. (1992) Phenylpropanoid metabolism biosynthesis of monolignols, lignans and neolignans, lignins and suberins, in Phenolic Metabolism in Plants (eds H.A. Stafford and R.K. Ibrahim). Plenum, New York, pp. 325-75. 

Katayama, T., Suzuki, T., Lourith, N. and Kurita, Y. (2005) Biosynthesis and stereochemistry of lignans and neolignans Stereoselective cross coupling of coniferyl alcohol and sinapyl alcohol in broad-leaved trees. Kami Parupu Kenkyu Happyokai Koen Yoshishu, 72, 84 9. 

Lewis NG, Davin LB. Evolution of lignan and neolignan biochemical pathways. In Isoprenoids and other natural products Evolution and function. Nes WD, ed. 1994. ACS Symposium Series, Washington, D.C. 

In the electrolysis of VIII and IX a mixture of C,0 and C,C coupling products (sym netrical, unsymmetrical, aryl-olefin, aryl-aryl, and olefin-olefin coupling) is obtained the products are related to lignans and neolignans [45]. 2,4,6-Tri-r-butylpheno-late is reversibly oxidized at —0.2 V (vs. SCE) to the phenoxy radical at a higher potential (+1.0V) the phenoxonium ion is formed irreversibly. Kinetics of the follow-up reactions are evaluated by CV [46]. 

From the biogenetic point of view, lignans and neolignans are produced by oxidative phenol couplings between two C6-C3 units. They have a variety of carbon skeletons as well as remarkable bioactivities . Several reviews on lignans and neolignans syntheses have appeared . 

Of phenolic oxidations using vanadium compounds, intramolecular oxidative phenolcoupling reactions are quite attractive from the viewpoint of natural products synthesis. A number of benzylisoquinoline alkaloids, lignans and neolignans are well known to be produced, in a key step, by oxidative radical coupling of open phenolic precursors. 

Wallis, A. R A. (1998) Structural diversity in lignans and neolignans. In Lewis, N. G., and Sarkanen, S. (eds). Lignin and Lignan Biosynthesis, American Chemical Society, Washington, DC. 

L. B. Davin N. G. Lewis, Phenylpropanoid Metabolism Biosynthesis of Monolignols, Lignans and Neolignans, Lignins and Suberins. In Recent Advances in Phytochemistry] Vol. 26 Phenolic Metabolism in Plants H. A. Stafford, R. K. Ibrahim, Eds. Plenum Press New York, 1992 pp 325-375. 

Apers S, Vlietinck A, Pieters L (2003) Lignans and neolignans as lead compounds. Phytochem Rev 2 201-207... 

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