Use of the Benzyl Mesylate for the Synthesis of Tetrahydrofuran Lignan: Syntheses of 7,8-trans, 7′,8′-trans, 7,7′-cis, and 8,8′-cis-Virgatusin Stereoisomers

Synthesis of all stereoisomers of 3,3'-dimethoxy-7,7'-epoxylignane-4,4'-diol and their plant growth inhibitory activity

All stereoisomers of 3,3'-dimethoxy-7,7'-epoxylignane-4,4'-diol were synthesized to examine the effect of stereochemistry on their plant growth inhibitory activity using lettuce and Italian ryegrass. The effect of structural modifications such as dehydroxylation, methoxylation and hydroxylation at the 9- and 9'-positions of the lignans on the activity was also studied. Most of the epoxylignanes showed higher plant growth inhibitory potency against ryegrass than against lettuce, and the inhibitory activity varied depending on the configurations of each position of the tetrahydrofuran ring (7-, 7'-, 8-, and 8'-positions of the epoxylignanes). Among the 9,9'-position-modified derivatives, the dehydroxy derivatives showed the highest potency. These results suggested that the plant growth inhibitory activity should be influenced by the structure of the epoxylignanes.

Stereoselective construction of tetra-substituted tetrahydrofuran compounds from benzylic hemiacetal in the presence of H2 and a Pd catalyst: stereoselective synthesis of a stereoisomer of (-)-virgatusin and its antimicrobiological activity

Tetra-substituted tetrahydrofuran compounds were stereoselectively prepared from benzylic hemiacetal in the neutral condition by employing the simple reagent, H(2), and a Pd catalyst. The stereoselective conversion of benzylic hemiacetal to two different stereoisomers of the tetrasubstituted tetrahydrofuran compound was observed. One of these tetrahydrofuran compounds was converted to the virgatusin stereoisomer to estimate its antimicrobiological activity.