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Org Lett ; 23(7): 2760-2765, 2021 Apr 02.
Artigo em Inglês | MEDLINE | ID: mdl-33730508


Asymmetric ruthenium-catalyzed C-H alkylations were enabled by a chiral C2-symmetric carboxylic acid. The mild cooperative ruthenium(II) catalysis set the stage for the assembly of chiral tetrahydrocarbazoles and cyclohepta[b]indoles with high levels of enantioselectivity at room temperature. Mechanistic studies by experiment and computation identified a fast C-H ruthenation, along with a rate- and enantio-determining proto-demetalation. The asymmetric induction was governed by weak attractive secondary dispersion interactions as found in NCI analysis of the key transition states.

Angew Chem Int Ed Engl ; 59(27): 11130-11135, 2020 Jun 26.
Artigo em Inglês | MEDLINE | ID: mdl-32129528


A ruthenium-catalyzed electrochemical dehydrogenative annulation reaction of imidazoles with alkynes has been established, enabling the preparation of various bridgehead N-fused [5,6]-bicyclic heteroarenes through regioselective electrochemical C-H/N-H annulation without chemical metal oxidants. Novel azaruthenabicyclo[3.2.0]heptadienes were fully characterized and identified as key intermediates. Mechanistic studies are suggestive of an oxidatively induced reductive elimination pathway within a ruthenium(II/III) regime.

Chemistry ; 25(71): 16246-16250, 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31820511


The widespread applications of substituted diketopyrrolopyrroles (DPPs) call for the development of efficient methods for their modular assembly. Herein, we present a π-expansion strategy for polyaromatic hydrocarbons (PAHs) by C-H activation in a sustainable fashion. Thus, twofold C-H/N-H activations were accomplished by versatile ruthenium(II)carboxylate catalysis, providing step-economical access to diversely decorated fluorogenic DPPs that was merged with late-stage palladium-catalyzed C-H arylation on the thus-assembled DPP motif.

Dalton Trans ; 47(31): 10439-10442, 2018 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-30004545


A series of [(PMP)Rh(CO)Cl]n+ complexes was synthesised and the impact of the metalloligands CuI, LiI and ZnII on the CO stretching band was analysed.

Angew Chem Int Ed Engl ; 57(33): 10625-10629, 2018 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-29882633


Manganese photocatalysts enabled versatile room-temperature C-H arylation reactions by means of continuous visible-light photoflow, thus allowing for efficient C-H arylations in 30 minutes with ample scope. The robustness of the manganese-catalyzed photoflow strategy was shown by visible light-induced gram-scale synthesis, clearly outperforming the batch performance.

Angew Chem Int Ed Engl ; 57(19): 5384-5388, 2018 05 04.
Artigo em Inglês | MEDLINE | ID: mdl-29474755


An inexpensive, nontoxic manganese catalyst enabled unprecedented redox-neutral carbonylative annulations under ambient pressure. The manganese catalyst outperformed all other typically used base and precious-metal catalysts. The outstanding versatility of the manganese catalysis manifold was reflected by ample substrate scope, setting the stage for effective late-stage manipulations under racemization-free conditions of a wealth of marketed drugs and natural products, including alkaloids, amino acids, steroids, and carbohydrates.