Ketone O-pentafluorobenzoyloximes Research Articles

4-Difluoromethylene-1-Pyrrolines by Intramolecular Heck Cyclization

A mechanistically interesting construction of fluoropyrrolines is reported. In the suggested mechanism, the oxidative addition product of Pd(0) insertion into the N-O bond of 2-(trifluoromethyl)allyl ketone O-pentafluorobenzoyloximes undergoes 5-endo-trig Heck cyclization (unfavorable by Baldwin’s rules) to give an α-trifluoromethyl Pd species that undergoes β-fluo­ride elimination to yield 4-difluoromethylene-1-pyrrolidines in poor to good yields. The unfavorable cyclization is overcome by the known β-arylation selectivity of trifluoromethyl groups in Heck reactions as rationalized by DFT calculations (R. J. Deeth, A. Smith, J. M. Brown J. Am. Chem. Soc. 2004, 126, 7144-7151). A stoichiometric amount of PPh3 was found to be required as the resultant F-Pd(PPh3)3 complex undergoes reductive elimination of F-PPh3, regenerating Pd(0) (V. V. Grustin Chem. Eur. J. 2002, 8, 1006-1014).

Heck-type 5- endo- trig cyclizations promoted by vinylic fluorines: Ring-fluorinated indene and 3 H-pyrrole syntheses from 1,1-difluoro-1-alkenes

Arylpalladium or aminopalladium species bearing a 2,2-difluorovinyl group undergo an unusual 5- endo alkene insertion followed by β-fluorine elimination. These processes provide a facile access to ring-fluorinated five-membered carbocyclic and heterocyclic compounds starting from an o-(3,3-difluoroallyl)phenyl trifluoromethanesulfonate and 3,3-difluoroallyl ketone O-pentafluorobenzoyloximes. In both systems, the two vinylic fluorine atoms are essential for Heck-type 5- endo- trig cyclizations.

Heck‐Type 5‐endo‐trig Cyclization Promoted by Vinylic Fluorines: Synthesis of 5‐Fluoro‐3H‐pyrroles.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of α‐Carbolines by Copper‐Catalyzed Radical Cyclization of β‐(3‐Indolyl) Ketone O‐Pentafluorobenzoyloximes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

5-endo Heck-type cyclization of 2-(trifluoromethyl)allyl ketone oximes: synthesis of 4-difluoromethylene-substituted 1-pyrrolines

2-(Trifluoromethyl)allyl ketone O-pentafluorobenzoyloximes undergo a palladium-catalyzed 5-endo mode of alkene insertion via oxidative addition of the N-O bond, followed by beta-fluorine elimination to produce 4-difluoromethylene-1-pyrrolines.

Synthesis of α-Carbolines by Copper-Catalyzed Radical Cyclization of β-(3-Indolyl) Ketone O-Pentafluorobenzoyloximes

Abstract Radical cyclization of β-(3-indolyl) ketone O-pentafluorobenzoyloximes proceeds by the treatment with a catalytic amount of copper powder in 1,2-dichloroethane to generate 3,4-dihydro-α-carbolines, which are oxidized to α-carbolines with chloranil.

Heck-type 5-endo-trig cyclization promoted by vinylic fluorines: synthesis of 5-fluoro-3H-pyrroles

A 5-endo-trig alkene insertion proceeds under palladium catalysis via aminopalladium species starting from 3,3-difluoroallyl ketone O-pentafluorobenzoyloximes, providing a facile access to 5-fluoro-3H-pyrroles.

Synthesis of 1‐Azaazulenes from Cycloheptatrienylmethyl Ketone O‐Pentafluorobenzoyloximes by Palladium‐Catalyzed Cyclization and Oxidation.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of 1-Azaazulenes from Cycloheptatrienylmethyl Ketone O-Pentafluorobenzoyloximes by Palladium-Catalyzed Cyclization and Oxidation

Abstract Various 1-azaazulenes are synthesized from cycloheptatrienylmethyl ketone O-pentafluorobenzoyloximes by treatment with a catalytic amount of Pd(dba)2–t-Bu3P (dba = dibenzylideneacetone) and triethylamine in the presence of MS 4A via alkylideneaminopalladium(II) intermediates generated by oxidative addition of the oximes to a Pd(0) complex.

Synthesis of Polycyclic Imines by Palladium‐Catalyzed Domino Cyclization of Di‐ and Trienyl Ketone O‐Pentafluorobenzoyloximes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Polycyclic Imines by Palladium-Catalyzed Domino Cyclization of Di- and Trienyl Ketone O-Pentafluorobenzoyloximes

Abstract Various cyclic imines, such as spiro imines and a fused bicyclic imine, are synthesized from dienyl and trienyl ketone O-pentafluorobenzoyloximes by the domino amino-Heck reaction. Treatment of the oximes with a catalytic amount of Pd(PPh3)4 and triethylamine gives polycyclic imines in high yields via alkylideneaminopalladium(II) intermediates generated in situ by the oxidative addition of the oximes to the Pd(0) complex.

Synthesis of Pyrrole Derivatives by Palladium‐Catalyzed Cyclization of γ,δ‐Unsaturated Ketone O‐Pentafluorobenzoyloximes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Palladium‐Catalyzed Synthesis of 1‐Azaazulenes from Cycloheptatrienylmethyl Ketone O‐Pentafluorobenzoyl Oximes.

AbstractFor Abstract see ChemInform Abstract in Full Text.

Synthesis of Pyrrole Derivatives by Palladium-Catalyzed Cyclization of γ,δ-Unsaturated Ketone O-Pentafluorobenzoyloximes

Abstract Various pyrrole derivatives are synthesized from γ,δ-unsaturated ketone O-pentafluorobenzoyloximes by treatment with catalytic amounts of Pd(PPh3)4 and triethylamine via alkylideneaminopalladium(II) intermediates generated by oxidative addition of the oximes to the Pd(0) complex.

Palladium-Catalyzed Synthesis of 1-Azaazulenes from Cycloheptatrienylmethyl Ketone O-Pentafluorobenzoyl Oximes

Abstract Substituted 1-azaazulenes are synthesized from cycloheptatrienylmethyl ketone O-pentafluorobenzoyloximes by the intramolecular Heck-type amination catalyzed by Pd(dba)2–(t-Bu)3P.

Synthesis of Pyridine and Isoquinoline Derivatives by the Palladium-Catalyzed Cyclization of Olefinic Ketone O-Pentafluorobenzoyloximes

Abstract Pyridines and isoquinolines are synthesized from olefinic ketone O-pentafluorobenzoyloximes by treatment with a catalytic amount of Pd(PPh3)4 in the presence of (n-Bu)4NCl and triethylamine.

Synthesis of Pyrrole Derivatives by the Heck-Type Cyclization of γ,δ-Unsaturated Ketone O-Pentafluorobenzoyloximes

Abstract Substituted pyrroles are synthesized from γ,δ-unsaturated ketone O-pentafluorobenzoyloximes by the intramolecular Heck-type amination of the olefinic moiety catalyzed by Pd(PPh3)4.