Synthesis of cis-syn-cis and cis-anti-cis linear triquinanes via photo-thermal metathesis  

Diverse cis-syn-cis and cis-anti-cis triquinane frameworks have been assembled by a simple synthetic protocol starting with substituted cage diones under microwave irradiation conditions. Thermal fragmentation of the cyclobutane ring play a key role in this process and milder reaction conditions have been employed in contrast to normal flash vacuum pyrolysis conditions. Here, thermal isomerization of the double bond has also been realized under the microwave irradiation conditions to afford the isomeric triquinanes at low temperature. These triquinane units are considered to be useful for the total synthesis of natural products and non-natural products containing fused cyclopentane rings