Asymmetric reactions intermolecular carbopalladation

As a typical intermolecular carbopalladation and termination, hydroarylation of alkynes are carried out extensively in the presence of HCO2H as a hydride source. Formation of regioisomers is observed in the reaction of asymmetric alkynes, and ratios depend on the nature of the substituents. High regioselectivity was observed in the reaction of the tertiary propargylic alcohol 14 to give 15 as a major product [5]. The (Z)-2-arylcinnamates 17, rather than 3-arylcinnamate 18, was obtained by the hydroarylation of methyl phenylpropiolate (16) [6]. 3-Substituled quinoline 21 was prepared by the regioselective hydroarylation of 19, followed by treatment of 20 with an acid without isolation [6]. 

The remainder of this section will focus on the different ways carbopalladation has been used to consuuct natural products. First, Sect. B will consider intermolecular cases. Then, Sect. C will discuss innamolecular carbopalladation showing the potential of the reaction to create small, medium, or large rings. Finally, domino reactions, cycloiso-merizations of enynes, and asymmetric reactions will be highlighted. 

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