181999-39-3Relevant articles and documents
Synthesis of heterocycles. Construction of the 1-azabicyclo[2.2.1]heptyl system by sequential ring-closure of acylic β-ammonio substituted radicals
Della, Ernest W.,Knill, Andrew M.
, p. 5805 - 5808 (1996)
Treatment of an irradiated solution of 1-methyl-1-(2-propynyl)-1-bis(2-phenylselenylethyl)ammonium iodide in tert-amyl alcohol with tributyltin hydride is found to be an effective procedure for the synthesis of 1,4-dimethyl-1-azoniabicyclo[2.2.1]heptane iodide. Attachment of a trimethylsilyl or phenyl substituent to the terminal carbon of the triple bond in the alkynyl salt leads to bridgehead-substituted bicylic heterocyclic salts.
Synthesis of nitrogen bridgehead bicyclic heterocycles via ring-closure of β-ammonio 5-hexenyl radicals
Della, Ernest W.,Knill, Andrew M.
, p. 7529 - 7533 (2007/10/03)
The 2-(3-methylenepiperidinyl)ethyl radical (6) displays considerable reluctance to ring-closure under conditions which its carbocyclic analog, the 2-(3-methylenecyclohexyl)ethyl radical (2), cyclizes essentially completely. Molecular mechanics calculations suggest that the increased activation barrier associated with ring-closure of 6 is the result of a higher than expected transition state energy. A study of the behavior of β-ammonio-substituted 5-hexenyl radicals, such as the 3,3-dimethyl-3-azonia-5-hexenyl radical (22), reveals that cyclization occurs readily. Treatment of 1-methyl-1-(2-(phenylselenyl)ethyl)-3-methylenepiperidinium iodide (20) with tributyltin hydride in tert-amyl alcohol yields the bridgehead nitrogen bicyclic heterocycle, 1,5-dimethyl-1-azoniabicyclo-[3.2.1]octane iodide (26), in excellent yield and without contamination, thus providing an attractive synthetic route to this hitherto unknown heterocyclic system.
