| Abstract
| - π−π stacking as a structural consideration in new Pd(II) phosphino-oxazolines, together with enantioselective Heck arylation and Pd(0) dba dynamics, are all reported
- A phosphino,oxazoline P,N-bidentate ligand, 4, containing 3,5-di-tert-butylphenyl groupshas been prepared. In the Heck arylation of dihydrofuran, 4 is shown to afford higher ee'sthan either 2 or 3, the unsubstituted and m-dimethylphenyl analogues, respectively. SeveralPd(0) complexes of 4 are reported. The exchange dynamics of Pd(4)(dba) are shown to involvean interconversion of diastereomers via an intramolecular process. The X-ray structure forPdCl2(4), 8, was determined by X-ray diffraction methods. Comparison of data with PdCl2(2), 9, and PdCl2(3), 10, suggests that differing amounts of π−π stacking influence thestructures of these relatively simple Pd complexes, with 9 and 10 revealing the strongestπ−π interactions. An estimation of the van der Waals energies involved in the interactionsupports a ca. 4 kcal/mol stabilization via π−π stacking.
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