Carbon-nitrogen bond formation intermolecular reactions

Intramolecular carbon-nitrogen bond formation is possible utilizing a catalytic system derived from Pd2(dba)3/P(2-tolyl)3, which gives enantiomerically enriched amine and amide products with either endocyclic or exocyclic chiral centers, e.g., 15 to give 16 (eq 15). Note that no decrease in enantiomeric excess is observed from substrate to product. In contrast, the intermolecular variant, e.g., reaction of 17 and 18 to give 19, conducted under identical reaction conditions, leads to products that are partially or fully racemized. Key to the success of the intermolecular process is the employment of bidentate ligands such as roc-BINAP or DPPF (eq 16). 

Scheme 192. Reaction of Alkenyl Epoxides and Aziridines Producing Heterocycles via Carbon-Heteroatom Bond Formation by (a) Intramolecular Allylation of Oxygen and Nitrogen Nucleophiles and (b) Intermolecular [3 + 2]-Cycloaddition with Heterocumulenes...

In these reactions, the nitrogen nucleophile is typically an amide, carbamate, or sulfonamide. Because of the low nucleophilicity of such nitrogen functions, no intermolecular 1,4-addition involving C—N bond formation is known. In all cases reported, the carbon-nitrogen coupling takes place in an intramolecular aminopalladation. 

Highly selective formation of cis-cycloadduct 53 from three-carbon tethered pyridones can be achieved through intermolecular hydrogen bonding. Compound 51a, lacking nitrogen substitution, yields exclusively the cis-53a when the photochemistry is conducted in benzene or toluene, but only the trans-isomer 52a when the reaction is run in DMSO or methanol. Solvent and concentration studies were consistent... 

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