TY - JOUR
T1 - A two-step, three-component queuing cascade leading to dihydrobenzoxepine and dihydrobenzazepine derivatives
AU - Yucel, Baris
AU - Valentić, Nataša
AU - Noltemeyer, Mathias
AU - De Meijere, Armin
PY - 2007
Y1 - 2007
N2 - A palladium-catalyzed reaction of methylenespiropentane (11) with iodobenzene (12) under typical Heck conditions [Pd(OAc)2, PPh 3, Et3N, DMF] produced a mixture of the unstable [3]dendralene 13 and allylidenecyclopropane 14 in 38 % yield. When an analogous reaction with iodobenzene was carried out in the presence of morpholine (25) and of tris(2-furyl)phosphane (TFP) instead of triphenylphosphane, the dienes 26, 28 and 31 were generated by nucleophilic trapping of π-allylpalladium intermediates 30 and 32. The cross coupling of methylenespiropentane (11) with the functionalized aryl iodides 33a-g in the presence of a palladium precatalyst [Pd(OAc)2, TFP, Et3N, DMF] at 80°C, 3 h, provided the seven-membered 3,4-dimethylene-substituted heterocycles 34a-g and 35b which, upon addition of dimethyl fumarate (19), underwent Diels-Alder reactions to furnish bicyclic and higher oligocyclic dihydrobenzoxepine and -benzazepine derivatives 36a-g and 37b, yet in rather moderate yields of 18-29% only. The overall process constitutes a one-pot, two-step, three-component queuing cascade.
AB - A palladium-catalyzed reaction of methylenespiropentane (11) with iodobenzene (12) under typical Heck conditions [Pd(OAc)2, PPh 3, Et3N, DMF] produced a mixture of the unstable [3]dendralene 13 and allylidenecyclopropane 14 in 38 % yield. When an analogous reaction with iodobenzene was carried out in the presence of morpholine (25) and of tris(2-furyl)phosphane (TFP) instead of triphenylphosphane, the dienes 26, 28 and 31 were generated by nucleophilic trapping of π-allylpalladium intermediates 30 and 32. The cross coupling of methylenespiropentane (11) with the functionalized aryl iodides 33a-g in the presence of a palladium precatalyst [Pd(OAc)2, TFP, Et3N, DMF] at 80°C, 3 h, provided the seven-membered 3,4-dimethylene-substituted heterocycles 34a-g and 35b which, upon addition of dimethyl fumarate (19), underwent Diels-Alder reactions to furnish bicyclic and higher oligocyclic dihydrobenzoxepine and -benzazepine derivatives 36a-g and 37b, yet in rather moderate yields of 18-29% only. The overall process constitutes a one-pot, two-step, three-component queuing cascade.
KW - π-Allylpalladium species
KW - Benzazepine
KW - Benzoxepine
KW - Bicyclopropylidene
KW - Methylenespiropentane
UR - http://www.scopus.com/inward/record.url?scp=34548083408&partnerID=8YFLogxK
U2 - 10.1002/ejoc.200700354
DO - 10.1002/ejoc.200700354
M3 - Article
AN - SCOPUS:34548083408
SN - 1434-193X
SP - 4081
EP - 4090
JO - European Journal of Organic Chemistry
JF - European Journal of Organic Chemistry
IS - 24
ER -