Optimization of the cyclization of cyclic and acyclic carbonates

August 14, 2024

• Title:       

  Optimization of the cyclization of cyclic and acyclic carbonates

• Image Source:

  Palladium-catalyzed asymmetric synthesis of 2-alkynyl oxacycles

• Mark:

  Table 1

• Associated context:

  To investigate the stereoselectivity of the cyclization, we prepared the diastereomeric disubstituted cyclic carbonates  3d and 3e (Table 1),[8] the relative stereochemistry of the to the exclusive formation of enyne 5 (Table 1, entry 1, 84%,  E/Z = 58:42). On repeating the reaction in the presence of arylboronic acid, the desired reactivity was restored, with 3d  and 3e leading to a complementary 9:1 mixture of THF  products 4d and 4e respectively (Table 1, entries 2 and 3).