The N-methoxy-N-methylamides (Weinreb amides) of carboxylic acids, N-protected amino acids and peptides are readily prepared from the acid chloride or mixed anhydride, or from the acid in the presence of 2-Chloro-1-methyl-pyridinium iodide: Synth. Commun., 25, 1277 (1995); or BOP Reagent (1H-Benzotriazol-1-yl-oxytris(dimethyl-amino)-phosphonium hexafluorophosphate): J. Org. Chem., 61, 4999 (1996). Reaction with Grignard or organolithium reagents gives ketones: Tetrahedron Lett., 22, 3815 (1981). Reduction with Lithium aluminum hydride, gives the aldehyde: Synthesis, 676 (1983). For subsequent conversion of Boc-amino acid derived aldehydes and ketones to pyrrole derivatives, see: J. Org. Chem., 61, 4999 (1996). Coupling with alkyl acetoacetates gives ? δ -diketo esters: Tetrahedron Lett., 29, 6467 (1988). For conversion to ɑ -diketones or ɑ -keto esters, see: J. Org. Chem., 54, 3913 (1989).
