Simple Modular Synthetic Approaches to Asymmetric NN′N′′, NN′C, or NN′P-Type Amido Pincer Ligands: Synthesis, Characterisation, and Preliminary Ligation Studies

‡ Corresponding author for the crystallographic characterisation of compound 1.

§ Corresponding author for the crystallographic characterisation of compound 3m•oxide.

Abstract

A simple modular approach is presented which has been directed towards the synthesis of potentially monoanionic NN′N′′, NN′C, and NN′P pincer-type ligands. These pincers incorporate an amide functionality derived from the skeletal structure of readily available 2-(2-aminophenyl)-4,5-dioxooxazoles. All of the pincers are synthesized in moderate yields (up to 74%) and are characterised by nuclear magnetic spectroscopy (NMR), elemental analyses, and infrared (IR) spectroscopy. X-ray crystallography is also performed on the chiral and achiral alkyl halide precursors and on an oxide derivative of a pincer with a NN′P-atom donor set. A palladium derivative of one of the NN′N′′-pincers is shown to be an active catalyst for the addition of an allyl group to various benzaldehydes using n-Bu₃Sn(allyl) as allyl source.

Key words

pincer - oxazoline - ligands - palladium complex - allyl group transfer

• References

• 1 New address: K. Herasymchuk, Department of Chemistry, Simon Fraser University, 8888 University Drive, Burnaby BC V5A 1S6 Canada.
• 2 Undergraduate research participant.
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