Figures & data
Scheme 1. (a) Prior art: Catalytic γ-lactam synthesis from unprotected 1° alkylamines; (b) Inspiration: traceless alkyl-alkyl cross-coupling using N-tosylhydrazones; (c) Original aim of this work: metal-free α-C–H alkylation of amines; (d) Problems and side reactions.
Scheme 2. König’s merger of photoredox catalysis with Wolff-Kishner-type reactivity of N-tosylhydrazones.
Scheme 3. Attempts at photocatalytic alkyl radical addition to N-tosylhydrazones.
Scheme 4. Further studies using other alkyl radical precursors.
Scheme 5. (a) Photoredox coupling of N,N-dimethylaniline 49 with N-Ts hydrazone 34. (b) Photoredox coupling of N-Ph pyrrolidine 52 with N-Ts hydrazone 34.
Scheme 6. Proposed mechanistic rationale for the generation of reduced hydrazone by-product 54 when using cyclic amine 52.
Scheme 7. (a) Photoredox coupling of N-Boc dimethylamine 61 with N-Ts hydrazone 34. (b) Photoredox coupling of N-Boc pyrrolidine 64 with N-Ts hydrazone 34.
Scheme 8. Attempted denitrogenative decomposition of N-Ts hydrazides 51 and 63.
