Cage Enlargement of 1,4-Bis(hydroxymethyl)pentacyclo2,5.03,8.04,7>octane to a Tetracyclo3,9.04,7>nonane System in Formic Acid

Article abstract of DOI:10.1246/bcsj.67.462

Cationic rearrangement of 1,4-bis(diarylhydroxymethyl)pentacyclo<4.2.0.0 2,5 .0 3,8 .0 4,7 >octanes (1) in formic acid gave new cage compounds, 8,8-diaryl-2-diarylmethylene-exo-5-(formyloxy)tetracyclo<4.3.0.0 3,9 .0 4,7 >nonan-7-ols (3) and new cage-degradation products, 5,5-diaryl-4-<4-(diarylmethylene)-2-cyclobutenyl>-2-cyclopenten-1-ones (4) along with Wagner-Meerwein rearrangement products, pentacyclo<5.3.0.0 2,5 .0 3,9 .0 4,8 >decanes (5; C 2 -bishomocubanes) and pentacyclo<5.3.0.0 2,6 .0 3,9 .0 4,8 >decanes (6; D 2h -bishomocubanes). 9,9-Diaryl-4-(diarylhydroxymethyl) pentacyclo<4.3.0.0 2,5 .0 3,8 .0 4,7 >nonan-1-ols (2) gave 4, 5, and 6 without the formation of 3.A Wagner-Meerwein 1,2-bond shift of 1 gave key intermediates 2 which were converted into 3 via homoallylic rearrangement, into 4 via pinacol-pinacolone-like rearrangement, or into 5 and 6 via Wagner-Meerwein rearrangement.