PET reactions of cis-dibenzoylalkenes: an efficient trans-reduction of C=C bond.

In contrast to its reaction under catalytic hydrogenation, the first instance of an exclusive and chemoselective trans-reduction of the ene part of derivatives of 5,6-dibenzoylbicyclo[2.2.2]oct-5-en-2-one has been reported under moderate photoinduced electron transfer (PET) conditions using triethylamine (TEA).

Face-selective Diels-Alder reactions between unsymmetrical cyclohexadienes and symmetric trans-dienophile: an experimental and computational investigation.

A combined experimental and theoretical study of the Diels-Alder reactions between 2-trimethylsiloxy-1,3-cyclohexadienes (2-11) and (E)-1,4-diphenylbut-2-ene-1,4-dione (1) is reported. Two diastereomeric products, 5-endo-6-exo- (nx) and 5-exo-6-endo- (xn) dibenzoyl derivatives, are possible with symmetric trans-dienophile (1). While in many cases 5-endo-6-exo product is preferred over the corresponding 5-exo-6-endo product, the product ratio nx:xn is found to vary with the position of substituents on the diene.

Steric-controlled excimer formation in naphthalene analogues of chalcone.

Naphthalene analogues of chalcone (typical vinylarenes) are well known for their intramolecular charge transfer (CT) process. The all four possible isomers NC1, NC2, NC3 and NC4 were observed to give structure-less broad CT bands, whereas, excimer formation at higher concentration was reported only for NC4 [Res. Chem.