TY - JOUR
T1 - The tertiary amino effect in heterocyclic synthesis
T2 - mechanistic and computational study of the formation of six-membered rings
AU - Groenen, L.C.
AU - Verboom, Willem
AU - Nijhuis, W.H.N.
AU - Reinhoudt, D.N.
AU - van Hummel, G.J.
AU - Feil, D.
PY - 1988
Y1 - 1988
N2 - The mechanism of the ring closure of [2-(1-pyrrolidinyl)phenylmethylene]-propanedinitrile (2a) to l,2,3,3a,4,5-hexahydropyrrolo[1,2-a]quinoline-4,4-dicarbonitrile (3a) has been studied by kinetic measurements using 1H-NMR spectroscopy. It could be shown that the rate-determining step consists of an intramolecular 1,5 hydrogen transfer, which is accompanied by charge separation within the- molecule. The calculated (AM1) and experimental (X-ray) molecular structure of 2a are in fairly good agreement. In the ground state geometry a 1,5 hydrogen transfer will most likely take place suprafacially. Subsequent rotation of the former vinyl group and C-C-bond formation, leading to a six-membered ring, also take place in a stereochemically defined way.
AB - The mechanism of the ring closure of [2-(1-pyrrolidinyl)phenylmethylene]-propanedinitrile (2a) to l,2,3,3a,4,5-hexahydropyrrolo[1,2-a]quinoline-4,4-dicarbonitrile (3a) has been studied by kinetic measurements using 1H-NMR spectroscopy. It could be shown that the rate-determining step consists of an intramolecular 1,5 hydrogen transfer, which is accompanied by charge separation within the- molecule. The calculated (AM1) and experimental (X-ray) molecular structure of 2a are in fairly good agreement. In the ground state geometry a 1,5 hydrogen transfer will most likely take place suprafacially. Subsequent rotation of the former vinyl group and C-C-bond formation, leading to a six-membered ring, also take place in a stereochemically defined way.
U2 - 10.1016/S0040-4020(01)86166-4
DO - 10.1016/S0040-4020(01)86166-4
M3 - Article
SN - 0040-4020
VL - 44
SP - 4637
EP - 4644
JO - Tetrahedron
JF - Tetrahedron
IS - 14
ER -