Through-Bond Interaction via Cyclobutane Relay Orbitals. Evaluation of the Question of Extended Conjugation in Belted [4,5]Dihomotropones
摘要:
The preparation of tricyclo[6.5.0.0(2,9)]trideca-3,6,10,12-tetraen-5-one (3), its dihydro derivative 16, and the structurally related carbinol 17 has been successfully realized. In a companion synthesis of the lower homolog 4, an inability to effect the desulfonylative ring contraction either of 26 or 29 was encountered. Although introduction of the ethylene bridge could be accomplished first as in 23, the ease with which this ketal isomerized to 24 precluded its further use in the pursuit of 4. Molecular mechanics calculations showed the dienone subunit in 4 to deviate significantly from planarity. This behavior is in striking contrast to the planar minimum energy conformations computed for [4,5]dihomotropone (2) and its higher vinylog 3. An evaluation of the spectral properties of 3 reveal this ketone not to be polarized. No evidence that could be construed to be a reflection of ground-state through-bond interaction was uncovered.
Through-Bond Interaction via Cyclobutane Relay Orbitals. Evaluation of the Question of Extended Conjugation in Belted [4,5]Dihomotropones
摘要:
The preparation of tricyclo[6.5.0.0(2,9)]trideca-3,6,10,12-tetraen-5-one (3), its dihydro derivative 16, and the structurally related carbinol 17 has been successfully realized. In a companion synthesis of the lower homolog 4, an inability to effect the desulfonylative ring contraction either of 26 or 29 was encountered. Although introduction of the ethylene bridge could be accomplished first as in 23, the ease with which this ketal isomerized to 24 precluded its further use in the pursuit of 4. Molecular mechanics calculations showed the dienone subunit in 4 to deviate significantly from planarity. This behavior is in striking contrast to the planar minimum energy conformations computed for [4,5]dihomotropone (2) and its higher vinylog 3. An evaluation of the spectral properties of 3 reveal this ketone not to be polarized. No evidence that could be construed to be a reflection of ground-state through-bond interaction was uncovered.
Through-Bond Interaction via Cyclobutane Relay Orbitals. Evaluation of the Question of Extended Conjugation in Belted [4,5]Dihomotropones
作者:Leo A. Paquette、Timothy J. Watson
DOI:10.1021/jo00098a032
日期:1994.9
The preparation of tricyclo[6.5.0.0(2,9)]trideca-3,6,10,12-tetraen-5-one (3), its dihydro derivative 16, and the structurally related carbinol 17 has been successfully realized. In a companion synthesis of the lower homolog 4, an inability to effect the desulfonylative ring contraction either of 26 or 29 was encountered. Although introduction of the ethylene bridge could be accomplished first as in 23, the ease with which this ketal isomerized to 24 precluded its further use in the pursuit of 4. Molecular mechanics calculations showed the dienone subunit in 4 to deviate significantly from planarity. This behavior is in striking contrast to the planar minimum energy conformations computed for [4,5]dihomotropone (2) and its higher vinylog 3. An evaluation of the spectral properties of 3 reveal this ketone not to be polarized. No evidence that could be construed to be a reflection of ground-state through-bond interaction was uncovered.