Understanding the influence of the trifluoromethyl group on the chemo-, regio-, and stereoselectivity of [3+2]-cycloadditions of thiocarbonyl S-methanides with α,β-unsaturated ketones. A molecular electron density theory study

Abstract

Experimentally (G. Mlostoń et al., J. Fluor. Chem. 190 (2016) 56-60), it has been found that the type of the obtained cycloadduct of the [3+2] cycloaddition (32CA) reaction of thiocarbonyl S-methanides with α,β-unsaturated ketones depends strongly on the location of the trifluoromethyl group. In the case of enones containing the CF3CH=CH moiety, the 32CA reaction occurs chemo-and regioselectively onto the C=C double bond giving trifluoromethylated tetrahydrothiophene derivatives. On the other hand, enones containing the CF3-C=O fragment react as carbonyl heteroethylenes leading to trifluoromethylated

On the Question of Stepwise [4+2] Cycloaddition Reactions and Their Stereochemical Aspects

“…Currently, in addition to conjugated 1,3-dienes, conjugated nitroalkenes [5][6][7] are tested quite frequently as hetero-analogues of the dienes. The role of hetero-analogues of ethene as components of the cycloaddition reaction includes molecular segments containing nitrogen [8,9], oxygen [10,11], sulphur [12,13], selenium [14], and others.…”