Tetracyanoethylene as an aromatizing agent

Abstract

(TCNE) has proven to be an extremely versatile chemical intermediate. 1 The reactions of TCNE with conjugated dienes have been well delineated. In contrast to normal Diels-Alder adductions 293 with conjugated acyclic and cisoid cyclic dienes, Spiro-compounds 4-6 are generated by cyclo

The Preparation of Hexaphenylcyclotrisilthiane and of Tetraphenylcyclodisilthiane1

“…They have shown that compounds containing six-membered siloxane rings (cyclic trimers) can be distinguished from similarly substituted eight-membered cyclic siloxanes by a characteristic shift in infrared absorption. Our somewhat comparable results with the fourand sixmembered cyclic silthianes (I and II) show that vibrational absorption spectra of both have identical bands except for a single shift from 13.45 µ for the dimer 1 to 13.63 µ for the trimer II. The six-membered cyclosiloxane ring shows a strong band at 9.8-9.9 µ.…”

Physical and Chemical Interaction of Homoconjugated Dienes with Tetracyanoethylene

“…A final comment concerns the surprising observation that 11 does not add TCNE within the timescale of our experiments, though 1,3-cyclohexadiene is known to react rapidly with this dienophile [24] with AH" = -31 kcal mol-1 [29]. The additional substituent present in 11 is likely to diminish the exothermicity of the addition reaction, since -as suggested by molecular models -there is some steric crowding in the bicyclic Diels-Alder product of 11 with TCNE even in the case of a sterically more favourable anti-attack of the latter.…”

“…Reactiorc of 2 with TCflE. It has been reported that 2 is efficiently dehydrogenated by TCNE furnishing benzene and tetracyanoethane (TCNA) [24]. Dehydrogenation can also be effected by treatment of 2 with 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) [as].…”

The Chemistry of Tetracyanoethylene

“…TCNE is used to increase the photosensitivity of some organic dyestuffs, viz., phthalocyanines (97). It can also be effectively employed in the aromatization of certain nonconjugated cycloalkadienes, where it functions as an efficient hydrogen acceptor (85). TCNE has found some use as a component in fuel mixtures (86), which burn to give electron-rich gases (48) and also in propellant fuel compositions (45).…”