Sanjoy K. Chowdhury

Nickel-catalyzed cyclizations of alkynyl enones and alkynyl enals

Substrates that possess an a,b-unsaturated carbonyl tethered to an alkyne have been utilized in a variety of nickel-catalyzed processes. Depending on ligand structure, reagent structure, reaction conditions, and workup conditions, several different monocyclic and bicyclic ring systems may be accessed from a common substrate. Evidence for a nickel metallacycle as a common intermediate is provided.

Stereochemistry of molybdenum(II) π-allyl complexes

The stereochemistry of molybdenum(II) π-allyl complexes is generally governed by intramolecular interactions between the ligand and the allyl group substituents. Interatomic repulsions are normally dominant. However, weak, attractive interactions may sometimes dictate conformational preferences. Examples include new organomolybdenum complexes containing pyrazole-derived chelating ligands. Structural information has been obtained from NMR spectroscopy and single crystal X-ray diffraction.

Polypyrazolylborate analogues without boron: Structural diversity in ligand design and metal complexes

Structural chemistry of organometallic complexes containing pyrazolederived polydentate ligands (without boron) has been reviewed in the context of current results from this laboratory.