Biogenesis of Neolignans

Chart 25. Schematic representation of coupling processes which lead from propenylphenol (88) and allylphenol (89) derived radicals, either by dimerization (x 2) or by addition of radical 90 [+(90)] to the indicated (in brackets) numbers of neolignans belonging to the 

In vitro, the coupling and follow-up steps are remarkably stereospecific (41, 129). a fact which was explained by the formation of a 

Chart 27. Postulated biosynthetic pathways to neolignan types of Lauraceae and 

The coupling of two units originated from an identical precursor is easily rationalized by the radical pairing mechanism (59), and experimental evidence testifies in favour of this postulate 111). The gene- 

Structural variation makes the neolignans a most interesting group of natural products from the chemical (Sections II—XII), practical (XIII) and biochemical (XIV) standpoint. Is the list of skeletal variants and their derivatives nearing completion  

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Fig. 7.3.10. Biogenesis of neolignans belonging to the bicyclo[3.2.1]octanoid (17, 23), futoenone (18,24), porosin (19), burchellin (25), and megaphone (20, 21) groups. Stereochemical indications are omitted in order to maintain the information as generally valid as possible...

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