摘要:
Cobalt(II) complex of P1 [Co(P1)], a new porphyrin that was designed on the basis of potential hydrogen bonding interactions in the metal-nitrene intermediate, is a highly active catalyst for olefin aziridination with azides. The [Co(P1)]-based system can be effectively employed for different combinations of aromatic olefins and arysulfonyl azides, synthesizing various sulfonylated aziridines in excellent yields. Besides its mild catalytic conditions, the Co-catalyzed aziridination process enjoys several attributes associated with the relatively low cost of cobalt and widely accessible arylsulfonyl azides. Furthermore, it generates stable dinitrogen as the only by-product.
摘要:
Novel methods of synthesizing heteroatom-containing porphyrins and metalloporphyrins are disclosed. Novel heteroatom-containing porphyrin and metalloporphyrin compounds are also disclosed. The new methods advantageously utilize metal-catalyzed cross-coupling and amination reactions to produce porphyrin compounds useful in a variety of practical applications.
摘要:
The cobalt(II) complex of new D2-symmetric chiral porphyrin 3,5-DiMes-ChenPhyrin, [Co(P2)], has been shown to be a highly effective chiral metalloradical catalyst for enantioselective cyclopropenation of alkynes with acceptor/acceptor-substituted diazo reagents such as α-cyanodiazoacetamides and α-cyanodiazoacetates. The [Co(P2)]-mediated metalloradical cyclopropenation is suitable to a wide range of terminal aromatic and related conjugated alkynes with varied steric and electronic properties, providing the corresponding tri-substituted cyclopropenes in high yields with excellent enantiocontrol of the all-carbon quaternary stereogenic centers. In addition to mild reaction conditions, the Co(II)-based metalloradical catalysis for cyclopropenation features a high degree of functional group tolerance.
摘要:
Cobalt(II) complexes of the D2-symmetric chiral porphyrins are effective catalysts for asymmetric cyclopropanation reactions with succinimidyl diazoacetate. The Co-catalyzed reaction is suitable for various olefins, providing the corresponding cyclopropane succinimidyl esters in high yields and excellent diastereo- and enantio-selectivity. The resulting enantioenriched cyclopropane succinimidyl esters can serve as convenient synthons for the general synthesis of optically active cyclopropyl carboxamides through mild reactions with a wide range of amine derivatives, including unprotected peptides and amino sugars
摘要:
A process for the preparation of a 1,1-cyclopropane(nitrile)(electron-acceptor), the process comprising treating an olefin with an acceptor/acceptor-substituted α-cyanodiazo reagent in the presence of a catalytic amount of a metal porphyrin catalyst.
摘要:
Novel methods of synthesizing heteroatom-containing chiral porphyrins and chiral metalloporphyrins and the novel chiral porphyrins and chiral metalloporphyrins themselves are disclosed. Metal complexes of the chiral porphyrins are prepared in high yields and shown to be active catalysts for highly enantioselective and diastereoselective cyclopropanation, aziridination, and epoxidation of alkenes under a practical one-pot protocol.
摘要:
A process for the asymmetric aziridination of an alkene comprising treating the alkene with a sulfonyl azide, preferably trichloroethoxysulfonyl azide, in the presence of a cobalt(II) porphyrin.
摘要:
Cobalt (II) complexes of porphyrins are effective catalysts for intramolecular nitrene insertion of C—H bonds with arylsulfonyl azides. The cobalt-catalyzed process can proceed efficiently under mild and neutral conditions in low catalyst loading without the need of other reagents or additives, generating nitrogen gas as the only byproduct. Using the simple tetraphenylporphyrin (TPP) as the ligand, the cobalt-catalyzed intramolecular amidation can be applied to primary, secondary, and tertiary C—H bonds and suitable for a broad range of arylsulfonyl azides, leading to the syntheses of various benzosultam derivatives in excellent yields