Intramolecular Pd-Catalyzed Carboetherification and Carboamination. Influence of Catalyst Structure on Reaction Mechanism and Product Stereochemistry

The intramolecular Pd-catalyzed carboetherification of alkenes affords 2-indan-1-yltetrahydrofuran
products in moderate to good yield with good to excellent levels of diastereoselectivity. The stereochemical
outcome of these reactions is dependent on the structure of the Pd catalyst. Use of PCy3 or P[(4-MeO)C6H4]3 as the ligand for Pd leads to syn-addition of the arene and the oxygen atom across the double
bond, whereas use of (±)-BINAP or DPP-benzene affords products that result from anti-addition. The
catalyst-induced change in stereochemistry is likely due to a change in reaction mechanism. Evidence is
presented that suggests the syn-addition products derive from an unprecedented transannular alkene
insertion of an 11-membered Pd(Ar)(OR) complex. In contrast, the anti-addition products appear to arise
from Wacker-type anti-oxypalladation. Studies on analogous Pd-catalyzed intramolecular carboamination
reactions, which afford 2-indan-1-ylpyrrolidines that result from syn-addition, are also described.