| Abstract
| - Metastable half-sandwich complexes of the type [Cp*ML(NMe2)2] (L = aminooxazolinate, M = Zr, Hf) rearrange via a carbodiimide intermediate to yield chiral, alkoxide-functionalized guanidinate complexes. A rationale for the observed diastereoselection is presented.
- Treatment of Cp*M(NMe2)3 (M = Zr, Hf) with both achiral and optically pure chiral aminooxazolineproligands HL yields metastable aminooxazolinate half-sandwich diamide complexes [Cp*ML(NMe2)2].These species undergo clean rearrangement via oxazoline ring-opening to carbodiimides followed byamide migratory insertion. The chiral-at-metal products contain tridentate alkoxide-functionalizedguanidinates, as confirmed by X-ray diffraction. In some of the chiral ligand systems, single diastereomersamples can be prepared, either by direct reaction or after recrystallization. As a result of the chelatestructure, no thermal conversion between diastereomers is observed. A mechanism leading to the observeddiastereoselection involving an intramolecular CH-π interaction in the major product is proposed.
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