Desaminierungsreaktionen, 39. Zerfall von 1‐Methylnorbornan‐2‐diazonium‐Ionen

Abstract

Desaminierungen von 1-Methyl-exo-2-norbornylamin (19) und der epimeren 2-Methyl-2-norbornylamine (32, 34) mit salpetriger Saure in Wasser ergaben ausschliefllich endo-2-Methyl-exo-2-norbornan01 (42a). Im Gegensatz dazu lieferte 1-Methyl-endo-2-norbornylamin (23) neben 42a auch 2-Methylbicyclo[3. Nitrous acid deaminations of 1-methyl-exo-2-norbornylamine (19) and of the epimeric 2-methyl-2-norbornylamines (32, 34) in water yielded endo-2-methyl-exo-2-norbornanol (42a) exclusively. In contrast, 1-methyl-endo-2-norbornylamine (23) afforded 2-methylbicyclo[3.1.l]heptan-2-ol (13a, 20%) and 1-methyl-endo-2-norbornanol (14a, 17%) in addition to 42a. The formation of bicyclo[3.1 .l]heptyl derivatives 13 is accentuated by better nucleophiles, as shown by photolyses of 1-methyl-2-norbornanone tosylhydrazone (35) in methanoVmethoxide, and in the presence of lithium azide. 14 and (in part) 13 are thought to originate from 7-bridged 1-methylnorbornyl cations (10). A substantial fraction of 13 stems from the open 2-methylbicyclo[3.1 .l]heptyl cation (12). The contributions of 10 and 12 have been elucidated by means of 3-D, labels. Introduction of an exo-3-methyl group (48, 50) enhances participation of the C-1 -C-7 bond. Cations 57 and 61 are the predominant intermediates generated from 1 ,exo-3-dimethylnorbornane-endo-2-diazonium ions (53). Less polar solvents (acetic acid, 2-ethylhexanoic acid) induce variations in product distribution which are attributed to increasing solvolytic displacement (kJ and ion pair collapse.Der Zerfall von exo-2-Norbornandiazonium-Ionen (2) in Wasser ergibt ausschlieBlich exo-2-Norbornanol (8); aus endo-2-Norbornandiazonium-Ionen (1) erhalt man exo-0