345620-19-1Relevant academic research and scientific papers
Investigation of an Electrocyclisation Route to the 7bH-Cyclopentindene System
Bradbury, Robert H.,Gilchrist, Thomas L.,Rees, Charles W.
, p. 3234 - 3238 (2007/10/02)
An approach to the synthesis of derivatives of 7bH-cyclopentindene ring system (1) has been explored in which two of the three rings are constructed by cyclisation reactions.The acetylenic alcohol (7) was prepared by coupling of 3-iodo-2-methylcyclopent-2-en-1-one (6) with the copper(I) salt of prop-2-ynyl alcohol tetrahydropyranyl ether.This was then converted into the Z,E-trienedione (2).On heating, this compound failed to undergo cyclisation; the only reaction observed was its isomerisation to the E,E-trienedione (10).Under forcing conditions it gave only indan-1-one.The cis-double bond of the trienedione system was fixed by incorporating it into a bicycloheptadiene system.Two such derivatives, (14) and (15), were prepared; both underwent smooth electrocyclic ring-closure on heating and the ylide (15) also cyclised further to give compound (19), which incorporates the required 7bH-cyclopentindene skeleton.
