Stereoselective Synthesis of Saturated Heterocycles via Palladium-Catalyzed Alkene Carboetherification and Carboamination Reactions

Abstract

The development of palladium-catalyzed carboetherification and carboamination reactions between aryl or alkenyl halides and alkenes bearing pendant heteroatoms is described. These transformations effect the stereoselective construction of useful heterocycles, such as tetrahydrofurans, pyrrolidines, imidazolidin-2-ones, isoxazolidines, and piperazines. The scope, limitations, and applications of these reactions are presented, and current stereochemical models are described. The mechanism of the product formation, which involves an unusual intramolecular syn-insertion of an alkene into a palladium-heteroatom bond, is also discussed in detail.

Palladium-catalysed cyclisation of alkenols: Synthesis of oxaheterocycles as core intermediates of natural compounds

“…However, terminal olefins 30 and threo - 9 underwent chlorocyclisation most probably due to the presence of an excess of chloride anions (Table 1, entries 10 and 11). Interestingly, this chlorocyclisation reaction proceeded with high trans -diastereoselectivity, which is in accordance with Wolfe´s TS model [17–18]. In both cases, only 2,3- trans diastereomers 55 and 58 were isolated in good yields.…”

Palladium(II)-Catalyzed Alkene Functionalization via Nucleopalladation: Stereochemical Pathways and Enantioselective Catalytic Applications

“…27 The resulting Pd II -aryl species 18 then undergoes intramolecular oxypalladation to give Pd-alkyl 19 , followed by reductive elimination to form a new C–C bond.…”

Migratory Insertion of Alkenes into Metal–Oxygen and Metal–Nitrogen Bonds

“…[93] In some cases, stereochemical evidence for syn aminopalladation by migratory insertion has been gained. Because reviews detailing known examples of palladium-catalyzed reactions involving an aminopalladation step are available, [94,95] this review focuses on the migratory insertion step.…”