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All eight stereoisomers of conidendrin were synthesized from (1 R,2 S,3 S)-1-(4-benzyloxy-3-methoxyphenyl)-3-(4-benzyloxy-3-methoxybenzyl)-2- hydroxymethyl-1,4-butanediol ((+)-4) and its enantiomer with high optical purity. The configurations at 4-positions of the conidendrin stereoisomers were constructed by intramolecular Friedel-Crafts reaction of protected 4. After conversion to tetrahydronaphthalene intermediate 7a, the 2- and 3-position of tetrahydronaphthalene structure 7a were converted to 3a- and 9a-position of (+)-α-conidendrin (3a), respectively. By the epimerization process of 2- or 3-position of 7a, the other diastereomers were obtained. All enantiomers were also synthesized from (−)-4. All stereoisomers of conidendrin with 97-100î were synthesized from common starting materials and its enantiomers with epimerization.

Improved methods for one-pot propargylation and Claisen rearrangement have been devised for natural lignans – matairesinol and α-conidendrin. The rearrangement was regiospecific, yielding only 2-methylbenzofuran derivatives.

The asymmetric allylation under the assistance of catalytic amounts of 3,3′-bis(2,4,6-triisopropylphenyl)-1,1′-binaphthyl-2,2′-diyl hydrogen phosphate (TRIP) allows the concise construction of the lignan scaffold from simple aldehydes and allylic bromides with full control of the two formed stereocenters. This young methodology has been employed to synthesize four naturally and pharmaceutically active lignans. Members of the dibenzylbutyrolactone, the tetraline, and the dibenzocyclooctadiene classes have been synthesized in 40–47% overall yield along four-step synthetic routes.

Methods for the preparation of phosphites and phosphates from chiral diols based on lignan backbones were developed. Four novel phosphites and one phosphate were synthesized and characterized. Sterically hindered diols showed diastereoselectivity in formations of phosphites, whereas non-hindered diols showed no selectivity.

The structures of the naturally occurring lignan hydroxymatairesinol (HMR) and TADDOL-like α -conidendrin-based chiral 1,4-diols (LIGNOLs) have been studied at DFT/B3LYP/TZVP level of theory, for the first time applying the density functional dispersion correction (DFT-D3) [1] and employing the BJ-damping (-D3(BJ)) [2] . This study establishes the necessity of treating the dispersion interactions properly in DFT optimizations. Several of the conformers received were not found in previous studies and the 4Ph4 structure received applying D3 is now published for the first time as a quantum chemically optimized structure.

An efficient C–H activation of primary benzylic positions by means of rhodium carbenoid induced C–H insertions is described. This key step was used in concise syntheses of (+)-imperanene and (−)-α-conidendrin.

The acid-catalyzed rearrangement of diaryl-dilactones, readily obtained by oxidation of ferulic acid derivatives, is examined as a synthesis route to aryltetralins. Two structures which have been proposed for the lignan, phyltetralin, are shown by synthesis of the two diastereomeric 1-veratryltetralins ( 3A ) and ( 3B ), to be untenable. Conidendrin has been converted to isolariciresinol tetramethyl ether ( 21 ) and comparison of empirical constants and spectra with those reported for phyltetralin strongly suggest that the lignan has the enantiomeric constitution ( 26 ).

The distribution of sapwood and heartwood was analyzed at three different height levels in Abiesgrandis infested and non-infested with balsam woolly aphid. In non-infested trees, there was a highly significant regression between percentage heartwood age and disk age and a less significant regression between percentage heartwood area and disk area. Aphid infestation increased both the number of annual rings of heartwood and the heartwood area. The amount of heartwood in the infested trees was highly variable and dependent upon the degree of aphid infestation. Phenolic composition of A. grandis was similar to western hemlock, with heartwood containing matairesinol, hydroxymatairesinol, conidendrin, and an unknown phenolic glucoside. Sapwood contained several leucoanthocyanidins. Aphid infestation did not alter the phenolic composition of the heartwood, but it did cause the occurrence of a new phenolic in the sapwood. The possible causes of the increased amounts of heartwood in infested trees are discussed.

The synthesis and structure of a new derivative of α-conidendrin, an extractive from western hemlock (Tsuga heterophylla [Raf.] Sarg.), are described. Elemental analyses together with high resolution nuclear magnetic spectroscopy enabled the structure to be designated as 2-naphthoic acid, 1,2,3,4-tetrahydro-3-hydroxymethyl-6,7-dimethoxy-4-(3′,4′-dimethoxyphenyl)-8-sulfonamide γ-lactone.

An all trans 1-aryl-2-methoxycarbonyl tetralin-3-carboxylic acid synthesised in 32% overall yield can be converted, at will, to either dimethyl conidendrin or dimethyl retrodendrin in one step.