Question

1. Reductive amination (Carey, Section 22.10) is an important C-N bond forming strategy widely used in the synthesis of biologically active natural product. It's a powerful and reliable strategy that avoids the problem of overalkylation that often accompanies direct alkylation of amines with alkyl halides (Figure 1). secondary amine r tiary amine quemary sa Figure 1: Yields are generally poor as product amines are more nucleophilic and can also react with halide. The result is often a mixture of amines in various states of alkylation. The reductive amination mechanism involves a one-or two-step procedure in which an amine and a carbonyl compound condense to afford an imine or iminium ion that is reduced in situ or subsequently to form an amine product (Figure 2). 0 R H (cat.) H(cat) RR2 RTR OH R. R R ,R* = H, alkyl, aryl R+=H -H.0 NR* it. Hi (cat) HR2R RR2 BIR Figure 2: Scheme for the reductive amination of aldehydes and ketones with primary and secondary amines. Using the general scheme outlined in Figure 2 as a guide, provide a detailed mechanism, excluding proton transfer reactions, for the reaction below. Draw intermediates in the boxes provided, use curly arrows to show the flow of electrons and depict sodium borohydride as a "hydride" ion (H). 1.) HN-CH 2.) proton transter ha 2) proton e r 2) proto transfer Hovech

Answer 1

NH₂ CH3 O NH₂ CH3 22) ploton transfer NUCHS Oxoniem con 1-H₂O proton tranfer Home Name omune NaB + -proton transfre N-Me amine