The palladium complex (bipy)Pd(CH 3 )NCC-H 3 + OTf -(2; bipy ) 2,2′-bipyridyl, OTf ) OSO 2 CF 3 ) has been found to undergo the novel sequential insertion of carbon monoxide and imine into the metal-carbon bond in a manner directly analogous to that observed in olefin/CO alternating copolymerizations. The structure of the insertion products, (bipy)Pd[C(Tol)HNRCOC-H 3 ] + OTf -, suggests that the unique combination of CO insertion, amide bond formation, carbonyl oxygen chelation, and resonance stabilization of the chelate ring provides the stabilization required for imine insertion to occur. a Measured by 1 H NMR at 30°C for 3a-d + CD3CN T 2 + 1a-d. b From plot of Keq vs 1/T from 25 to 75°C.

A new palladium-catalyzed route to prepare 1,3-oxazolium-5-oxides (i.e., Münchnones) directly from imine, carbon monoxide, and acid chloride building blocks has been developed. This provides a straightforward catalytic synthesis of Münchnones and is amenable to generating a diverse range of products by simple modification of the imine or acid chloride starting materials. Münchnones are vital synthetic intermediates to a variety of heterocyclic and peptide-based molecules. As such, this methodology has been utilized to design a new catalytic synthesis of alpha-amino acid derivatives via a one-pot coupling of imines, carbon monoxide, and acid chloride followed by alcohol. The latter represents the first reported catalytic synthesis of alpha-amino acids directly from imine and carbon monoxide building blocks.

One of the most facile routes to prepare carboxylate‐substituted imidazolines is by the palladium‐catalyzed coupling of an imine, carbon monoxide, and an acid chloride. In this reaction, a peptide unit is constructed and directly incorporated into the heterocyclic core (see scheme).

A new palladium-catalyzed synthesis of 3-amido-substituted beta-lactams is reported. This process involves the one-pot coupling of four components, imines, carbon monoxide, and acid chloride, providing a flexible route to construct this class of heterocycle. The generation of beta-lactams with two different imines can also be accomplished, providing a method to assemble these products with independent control over five separate substituents.

Ein besonders einfacher Zugang zu Carboxylatoimidazolinen ist die palladiumkatalysierte Kupplung von Kohlenmonoxid, einem Imin und einem Säurechlorid. Bei dieser Reaktion wird eine Peptideinheit gebildet und in situ in das Heterocyclengerüst eingebaut (siehe Schema).

The palladium insertion polymerization catalysts (bipy)Pd(CH3)L+OTf- have been found to mediate a second class of polymerization reaction:  the ring-opening polymerization of heterocycles. Unlike traditional cationic ring-opening processes, this polymerization is found to proceed via an unusual series of metal-based reactions, including novel steps which allow the coupling of insertion monomers (CO and norbornene) with ring-opened polymers.

No abstract

Approach to α-Amino Acid Derivatives. -A new method to prepare muenchnones as well as α-amino acid derivatives is described. -(DHAWAN, R.; DGHAYM, R. D.; ARNDTSEN*, B. A.; J. Am. Chem. Soc. 125 (2003) 6, 1474-1475; Dep. Chem., McGill Univ., Montreal, Que. H3A 2K6, Can.; Eng.) -Lindner 25-142