A Highly Regio- and Stereoselective Carbocupration of Fluoroalkylated Internal Alkynes: A Short Total Synthesis of the Antiestrogenic Drug Panomifene
摘要:
A highly regio- and stereoselective carbometalation reaction of fluoroalkylated internal alkynes with organocopper reagents is described. This reaction is utilized successfully in the short, stereoselective total synthesis of the antiestrogenic drug panomifene.
The carbometallation reactions of fluoroalkylated internal alkynes with various organocopper reagents derived from organolithium, Grignard, and organozinc reagents were examined. All carbocupration reactions proceeded smoothly in a highly regio- and stereo-selective manner to give the corresponding vinylcopper intermediates. The intermediates reacted with H+ smoothly, leading to the trisubstituted
Remarkable access to fluoroalkylated trisubstituted alkenes via highly stereoselective cobalt-catalyzed hydrosilylation reaction of fluoroalkylated alkynes
Hydrosilylation reaction of various fluoroalkylated alkynes with Et3SiH in the presence of a catalytic amount of Co2(CO)8 was investigated. The hydrosilylation of the alkynes having fluoroalkyl and aryl groups took place smoothly with good regioselectivity (ca. 80:20). In sharp contrast, the reaction of the alkynes having a fluoroalkyl group and a benzyl-type substituent, or various propargyl alcohols gave the corresponding vinylsilanes in an excellent regio- and stereoselective manner. Treatment of the vinylsilanes with various aldehydes in the presence of Zn(OTf)2 and TBAF afforded the coupling products in good yields.
A sequential highly stereoselective hydroboration and Suzuki–Miyaura cross-coupling reaction of fluoroalkylated internal acetylenes: a practical one-pot synthesis of fluoroalkylated trisubstituted alkenes
The one-pot synthesis of trisubstitutedalkenes starting from fluoroalkylated internal alkynes was investigated. Hydroboration of the alkynes proceeded in a highly regio- and stereoselective manner to give the corresponding vinylboranes in excellent yields. Without isolation, treatment of the vinylboranes with various aryl halides under the Suzuki-Miyaura cross-coupling conditions gave the fluoroalkylated
Intermolecular Pauson–Khand reaction of fluoroalkylated alkynes with 2-norbornene or 2,5-norbornadiene at the reflux temperature of dichloroethane proceeded smoothly to give the corresponding cyclopentenone derivatives in high yields as a mixture of regioisomers. On the other hand, intramolecular Pauson–Khand reaction of fluorine-containing 1,6-enyne proceeded in the presence of NMO or TMANO to give
A Facile Regiocontrol in the Palladium-Catalyzed Annulation of Fluorine-Containing Internal Alkynes with Variously Substituted 2-Iodoanilines: A New Regioselective Synthesis of 2- or 3-Fluoroalkylated Indole Derivatives
Treatment of various types of fluoroalkylated alkynes with o-iodoaniline in the presence of Pd(PPh3)4 in DMF at 80 °C for 8 h mainly gave 2-fluoroalkylated indoles in high yields. The use of P(o-Tol)3 instead of PPh3 as a ligand led to the preferential formation of 3-fluoroalkylated indoles in high yields. Interestingly, the reaction of trifluoromethylated alkynes bearing a benzylic substituent afforded