The Trindene Trianion

Article abstract of DOI:10.1021/ja00523a025

The lithium salt of the trindene trianion (6) is synthesized in four steps from cyclopentanone.Bromination and debromination, as summarized in Scheme III, convert trindane (octahydro-1H-trindene,14) into the dihydro-1H-trindenes,16a and 16b, and these with n-butyllithium in tetrahydrofuran give 6.The formation of the trianion is evidenced by quenching with deuterated water yielding the required trideuterio derivatives of 16a,b.When only 2 mol of n-butyllithium is used, the dianion 18 forms instead, as evidenced by reaction with deuterated water yielding molecules of 16a,b containing two allylic deuterium atoms.Sandwich molecules, assigned structures 19a,b, containing two irons, are produced when the dianion is combined with ferrous chloride, and only traces of sandwiches containing three iron atoms (presumably 9 with M = Fe) are detected in the corresponding rection product of 6.A product hoped for, polymer 5, could not be identified.The trindene trianion, although it contains multiple charges in one ?-electron system, is a favorable species because its rings are all five and six membered, because its highest occupied molecular orbital is low in energy, and because its lowest unoccupied molecular orbital is high in energy.