## 3 Potential Applications in Biological Studies
### Heterocyclic Compounds
A range of substrates bearing different functionalities was examined, as well as other thia- or aza-heterocyclic-based enones. Generally, the expected products were obtained in very good yields and uniformly excellent diastereoselectivity (>20:1) was observed for all prepared compounds. [PERSON] and co-workers developed an efficient Pd-catalyzed formal [5+3] cycloaddition process to prepare _N,O_-containing eight-membered heterocycles **126** (Scheme 60) [133]. In this work, zwitterionic allypalladium intermediates were generated in situ from vinylethylene carbonates **6**, which acted as 1,3-dipolarophiles in the cycloaddition. Under this Pd-catalyzed protocol, the reaction between _N_-iminoquinazolinium yildes **125** and carbonates **6** provided tricyclic compounds **126** in high yields with excellent regioselectivities. The optimal conditions were applied to alkyl- or aryl-substituted vinylethylene carbonates and different azomethine mines, including _N_-quinazolinium and _N_-isquinolin ylides, providing the expected [5+3] cycloadducts. The reaction mechanism involves the formation of the zwitterionic allypalladium intermediate **A**, which adds to the azomethine mine. The allypalladium intermediate **B** formed subsequently undergoes _N_-alkylation, leading to the [5+3] cycloaddition product **126** (Scheme 60). **Scheme 60. ** Pd-catalyzed formal [5+3] cycloaddition process to prepare _N,O_-containing eight-membered heterocycles **126**. [PERSON] and co-workers developed an air- and water-tolerant manganese(I) catalyst to perform the C-H allylation of heteroarenes **127** and arenes **128** with vinyl carbonates **14** through \"in-water\" decarboxylulative C-H/C-O cleavages (Scheme 61) [134]. In a typical procedure, aromatic compounds were reacted at 100 \({}^{\circ}\)C for 16 h with an excess of carbonate **14** in the presence of MnBr(CO)\({}_{5}\) (10 mol%) and NaOAc (20 mol%), using trifluoroethanol (TFE) or water as the solvent. C-H Allylations of indoles **127**, for instance, proceeded with good yields and high levels of chemo-, site-, and regioselectivity. In 2017, [PERSON] and co-workers [135] explored the domino C\(-\)H/\(N-\)H allylation of arylimitates under cobalt(III) catalysis (Scheme 62). In this work, the combined C\(-\)H and \(N-\)H allylation was reported for the one-step synthesis of isoquinolines. The reaction between different vinyl carbonates **14** and substituted arylimitates **131** delivered the desired decorated vinyl isoquinolines **132** in good yields. The protocol was extended to arylimitates **131** bearing electron-donating or electron-withdrawing groups, such as fluorine, chlorine, ester, ketone, and amide groups. The method was also suitable for carbonates **14** bearing aryl groups. In 2019, [PERSON] and co-workers reported the synthesis of oxazolidinones **133** through the carboxylic cyclization of anilines **63** and cyclic carbonates **1** (Scheme 63) [136]. The protic ionic liquid 1,8-diazobicyclo[5.4.0]-7-undecenium imidazoline [HDBU][Im] was used as a bifunctional catalyst under mild reaction conditions and without the addition of conventional solvents. Using this new protocol, a total of seventeen oxazolidinones **133** with different functional groups were obtained, such as Cl, Br, CH\({}_{3}\), OCH\({}_{3}\), and NO\({}_{2}\), with yields in the range of 61-92% after 6 h of reaction. Some of the advantages of this protocol are the low catalyst load, the wide functionality tolerance, and the convenient recycling of the catalyst. In the same year, [PERSON] and co-workers described the synthesis of a new heterogeneous catalyst, the ionic liquid 1-butyl-3-methylimidazol acetate ([bmim][OAc]) immobilized on MIL-101-NH\({}_{2}\), denoted as IL(OAc\({}^{-}\))-MIL-101-NH\({}_{2}\). This catalyst was used in the reaction between phenylalanine **63** and propylene carbonate **1b** to generate the oxazolidinones of interest **133** (Scheme 64) [137].