195734-34-0Relevant academic research and scientific papers
The nucleophilic 5-endo-trig cyclization of 1,1-difluoro-1-alkenes: Ring-fluorinated hetero- and carbocycle synthesis and remarkable effect of the vinylic fluorines on the disfavored process
Ichikawa, Junji,Wada, Yukinori,Fujiwara, Masaki,Sakoda, Kotaro
, p. 1917 - 1936 (2007/10/03)
The disfavored 5-endo-trig cyclizations have been accomplished for 1,1-difluoro-1-alkenes with nitrogen, oxygen, sulfur, and carbon nucleophiles by taking advantage of the properties of fluorine. β,β-Difluorostyrenes bearing tosylamido, hydroxy, or methylsulfinyl group at the o-position undergo intramolecular nucleophilic substitution with a loss of the vinylic fluorine, leading to 2-fluorinated indole, benzo[b]furan, and benzo[b]thiophene in high yields, 1,1-Difluoro-1-butenes bearing homoallylic tosylamido, hydroxy, mercapto, or iodomethyl group also successfully cyclize via a 5-endo-trig process with the in situ generated intramolecular nucleophiles to afford 2-fluoro-2-pyrroline, 5-fluoro-2,3-dihydrofuran, 5-fluoro-2,3-dihydrothiophene, and 1-fluorocyclopentene. The two vinylic fluorines proved to be essential and play a critical role in these 'anti-Baldwin' cyclizations.
5-endo-Trigonal cyclization of o-substituted gem-difluorostyrenes: Syntheses of 2-fluorinated indoles, benzo[b]furans and benzo[b]thiophenes
Ichikawa, Junji,Wada, Yukinori,Okauchi, Tatsuo,Minami, Toru
, p. 1537 - 1538 (2007/10/03)
β,β-Difluorostyrenes bearing tosylamido, hydroxy or methylsulfinyl groups at the o-position undergo intramolecular substitution of the nitrogen, oxygen or sulfur with loss of fluorine via a 5-endo-trigonal process leading to 2-fluorinated heterocyclic sys
