## 2 Applications in Chemistry
### Substitution Reaction
In this sense, racemic vinyl-substituted cyclic carbonates **6** are important substrates for copper-mediated S\({}_{\text{N}}\)2 reactions to access useful hydroxyl  
Figure 17: Synthesis of 1,3-bis-arylthiophenepan-2-ols **18** by incorporation of two thiol. functionalities **9** and **21** in a single step (Table 1, entries 1-3) [65], or for combining a palladium catalytic system and a boron reagent to obtain chiral alcohols **12** and ethers **8** (Table 1, entries 4-6) [66]. [PERSON] and co-workers [65] explored the allyl-boryl coupling of a series of substituted vinyl cyclic carbonates **6** with B\({}_{2}\)pin\({}_{2}\)**22** in the presence of CuCl, Cs\({}_{2}\)CO\({}_{3}\), and the \(N\)-heterocyclic carbene ligand **L1** (Table 1, Figure 2). Several \(E\)-configured boly-lated products **9** were obtained with 33-65% yields within 16 h at room temperature (Table 1, entry 1). When performed in the absence of ligand and with a higher amount of base, the allyl_alkyl coupling reaction with diborylmethane **23** generated compound **9** with 48-82% yields (Table 1, entry 2). Under similar conditions but using 1,2-bis(di-_tert_-butylphosphinomethyl)benzene **L2** (Figure 2) as the ligand, the selective allyl-boryl coupling of vinyl cyclic carbonates **6** with B\({}_{2}\)pin\({}_{2}\)**22** led to the corresponding (\(Z\))-stereoisomers, which were converted with 37-55% yields into the boracycles **20** (Table 1, entry 3) [65]. Finally, the versatility of (\(E\))-allylic and homoallylic borylated products **9** was demonstrated through the in situ copper-catalyzed S\({}_{N}\)2\({}^{\prime}\) allyl-boryl and allyl-alkyl couplings, followed by oxidative work-up. Thus, (\(E\))-configured but-2-ene-1,4-diols and pent-2-ene-1,5-diols were isolated with 27-59% and 42-58% yields, respectively. In the presence of a synergistic catalytic system formed by an in situ generated chiral palladium complex and a boron reagent, the asymmetric allylic substitution of racemic vinyl cyclic carbonates **6** with water and hydroxyl reagents provided a series of tertiary alcohols and ethers **8** in high yields (Table 1) [66]. The synthesis of tertiary alcohols **12** was performed by using a system containing phenylboronic acid **24**, Pd\({}_{2}\)(dba)\({}_{3}\).CHCl\({}_{3}\), [PERSON]'s ligand [(\(R\))-**13**] (Figure 2), and water (10 equivalent). The corresponding products were obtained with 82-98% yields (80-98% _ee_) after 16 h at 40 \({}^{\circ}\)C in THF (Table 1, entry 4). By changing to [PERSON]'s ligand (\(S\),\(S\),\(S\))-**L4** (Figure 2) and to triethylborane **25** as the boron reagent, the alcohols **12** were isolated with 61-87% yields and high enantioselectivity (80-98% _ee_) (Table 1, entry 5). An enantioselective allylic etherification process was developed, involving reaction of hydroxyl reagents with racemic vinyl cyclic carbonates **6** in the presence of (\(R\))-**L3** and triethylborane **25** to provide the desired ethers **8** (56-97% yields; 37-98% _ee_) (Table 1, entry 6). Figure 2: Scope of the ligands employed in the synthesis of compounds **8**, **9**, **12**, and **21**.