Intramolecular trans-Carbocarbonation of Internal Alkynes by a Cascade of Formal anti-Carbopalladation/Cyclopropanol Opening.

An intramolecular cascade reaction consisting of a formal anti-carbopalladation terminated by the ring-opening of a cyclopropanol unit is presented. The products, which involve tetrasubstituted alkene units embedded in an oligocyclic ring system, are generated in moderate to excellent yield. The opening of the cyclopropanol unit leads to a keto group in the γ-position to the emerging double bond.

trans-Carbocarbonation of Internal Alkynes through a Formal anti-Carbopalladation/C-H Activation Cascade.

An intramolecular Pd-catalyzed cascade reaction is presented that consists of a formal anti-carbopalladation of a C-C triple bond followed by C-H activation. As a result, oligocyclic ring systems with an embedded tetrasubstituted double bond are formed. The key to success in affording the trans geometry of the emerging double bond are alkyne units with residues that must not undergo β-hydride elimination (e.

Intramolecular trans-Dicarbofunctionalization of Alkynes by a Formal anti-Carbopalladation/Stille Cascade.

An intramolecular Pd-catalyzed trans-dicarbofunctionalization of internal alkynes using aryl bromides and aryl stannanes is presented. Tetrasubstituted double bonds embedded in an oligocyclic ring system are obtained in a regio- and diastereoselective fashion. The transformation features a broad substrate scope and functional-group tolerance.