Transition state analysis on regioselectivity in [2+2] photocycloaddition reactions of substituted 2-cyclohexenone with cycloalkenecarboxylates

(+)-Camphor Derivative Induced Asymmetric [2 + 2] Photoaddition Reaction

“…On the basis of the above analysis, only the head-to-tail adduct was observed as a single regioisomer in this process. Indeed, the excellent regioselectivity of this reaction was not surprising for us because the similar situation had been well documented in previous work and also could be explained in terms of the transition state analysis on the [2 + 2] photoaddition reaction by Somekawa and co-workers, in which the calculations showed that the transition state energy barriers for the HT adducts were lower than those for the HH adducts, leading to the selectivity preference. However, to our delight, a good diastereoselectivity with an 83% diastereomeric excess ( de ) was achieved by HPLC analysis.…”

Two pairs of enantiomeric α-pyrone dimers from the endophytic fungus Phoma sp. YN02-P-3

“…6 The course of the addition reaction and the resulting regioselectivities have remained a topic of great interest in this area. 7,8 a-Pyrone is a simple heterocyclic dienone system, 9 which is frequently used as the substrate of intramolecular photochemical reactions, in order to investigate the intermolecular cycloaddition reactivity. [10][11][12] During our continuing search for novel bioactive secondary metabolites from endophytic fungi, Phoma sp.…”

Crystal Structure of Imide-Amide between Kemp's Acid and L-Prolinol

“…1 We are thus searching for some host compounds to make coordination with enones or alkenes, as guest compounds, by hydrogen bonds. Bach et al selected Kemp's imide as the starting material for a chiral host.…”