Reactivity umpolung is an important concept in organic chemistry. Established reactivity umpolung mainly focuses on the aldehyde and umpolung of amide carbonyl group is not known. In this report, we ...describe a process to obtain the umpolung reactivity of tertiary amide. This process hinges on the efficient reductive stannylation catalyzed by Ir/silane and facile Sn−Li exchange. By leveraging this umpolung reactivity, drug Fluoxetine was derivatized to 12 different analogues via reacting with various electrophiles and four biologically active molecules were prepared concisely. This unlocked umpolung reactivity of tertiary amide is expected to find applications to synthesize complex amines from amides.
Amide carbonyl group usually serves as the electrophile, which can react with various nucleophiles. The current work shows a process to achieve the umpolung reactivity of tertiary amide carbonyl group. By leveraging this strategy, tertiary amide can react with a wide range of electrophiles to produce complex amines.
Phenols are important organic molecules because they have found widespread applications in many fields. Herein, an efficient and practical approach to prepare phenols from benzoic acids via simple ...organic reagents at room temperature is reported. This approach is compatible with various functional groups and heterocycles and can be easily scaled up. To demonstrate its synthetic utility, bioactive molecules and unsymmetrical hexaarylbenzenes have been prepared by leveraging this transformation as strategic steps. Mechanistic investigations suggest that the key migration step involves a free carbocation instead of a radical intermediate. Considering the abundance of benzoic acids and the utility of phenols, it is anticipated that this method will find broad applications in organic synthesis.
Organic molecules with light‐modifiable reactivity are important in many fields because they can serve as the “switch” for light to trigger chemical processes. Herein, we disclose a new type of ...stable non‐twisted amides, the reactivity of which can be turned on by light as acyl transfer reagents. Upon photo‐activation, these amides react with various nucleophiles including amines, phenols, hydroxide, thiols, boronic acids, and alkynes either under metal‐free or metal‐catalysis conditions. This reactivity hinges on the design and synthesis of a photo‐activatable reagent (7‐nitro‐5,6‐dihydrophenanthridine), which undergoes self‐aromatization enabled by an internal oxidant under light. This masked acyl donor group is anticipated to be useful in scenarios where light is preferred to trigger a chemical process.
A new type of stable amides is synthesized, which can react with various nucleophiles like acyl chlorides under light irradiation. This controllable switched‐on reactivity hinges on a rational‐designed photo‐activatable masked acyl donor reagent.
The iron-catalyzed highly Markovnikov-type selective and enantioselective hydrosilylation of terminal aliphatic alkenes with good functional group tolerance is developed. This operationally simple ...protocol uses earth-abundant transition metal catalyst, readily available aliphatic alkenes and hydrosilanes to construct valuable chiral organosilanes with better than 99% ee in most cases. The chiral aliphatic alkan-2-ol and chiral dihydroxysilane as an analogue of ketone could be efficiently synthesized via further derivatization of chiral organosilanes without any racemization.
Fabricating ultrathin two-dimensional (2D) covalent organic framework (COF) nanosheets (NSs) in large scale and high yield still remains a great challenge. This limits the exploration of the unique ...functionalities and wide range of application potentials of such materials. Herein, we develop a scalable general bottom-up approach to facilely synthesize ultrathin (<2.1 nm) imine-based 2D COF NSs (including COF-366 NSs, COF-367 NSs, COF-367-Co NSs, TAPB-PDA COF NSs, and TAPB-BPDA COF NSs) in large scale (>100 mg) and high yield (>55%), via an imine-exchange synthesis strategy through adding large excess amounts of 2,4,6-trimethylbenzaldehyde into the reaction system under solvothermal conditions. Impressively, visualization of the periodic pore lattice for COF-367 NSs by a scanning tunneling microscope (STM) clearly discloses the ultrathin 2D COF nature. In particular, the ultrathin COF-367-Co NSs isolated are subject to the heterogeneous photocatalyst for CO2-to-CO conversion, showing excellent efficiency with a CO production rate as high as 10 162 μmol g–1 h–1 and a selectivity of ca. 78% in aqueous media under visible-light irradiation, far superior to corresponding bulk materials and comparable with the thus far reported state-of-the-art visible-light driven heterocatalysts.
The Minisci alkylation is useful to functionalize aromatics via alkyl radical addition. Current approaches to prepare alkyl radicals follow either oxidative or reductive pathways from various ...functional groups. Developing new strategy beyond these traditional methods remains elusive yet highly significant. In this article, we present a redox-neutral and catalyst-free protocol to engender alkyl radicals in the context of trifluoromethylation and general alkylation of arenes. This protocol, via the Norrish type I concept to produce alkyl radicals, accommodates various functional groups and delivers the product in good yields. This method identified a series of compounds as the trifluoromethylation and alkylation reagents assisted by light. It is expected that these compounds can find potential applications in other radical-involved reactions.
Herein, we reported a protocol to access the enamide via employing carboxylic acid and alkenyl isocyanate as the precursors promoted by DMAP without involving any metal catalysts and dehydration ...reagents. This protocol is simple and practical and tolerates numerous functional groups. Considering the simplicity, the ready availability of both starting materials, and the significance of the enamides, we expect that this reaction will find broad application.
Here we show that a primary amine can engage in the nucleophilic addition to an aldehyde to synthesize an alcohol following preactivation of the amine. The enabling reagent for this radical-polar ...crossover process is CrCl2. This reaction is selective for aldehydes and compatible with numerous functional groups, which are not tolerated under classical Grignard-type conditions. Complementary to the well-established imine synthesis, this deaminative alcohol synthesis can broadly expand the chemical space constructed by aldehydes and amines.
Amide derivatization is useful to access valuable organic compounds considering the ready availability of molecules containing amide functionality. Current methods to derivatize amide mainly focus on ...the synthesis of carbonyl‐containing compounds and amines. Incorporating both parts of the initial amide into the new derivatives is rare. Herein, we describe a simple and practical amide derivatization through amino acid insertion to prepare more complex amides. This insertion is applicable to a wide range of amino acids and more importantly, the chiral information is completely conserved during the insertion. Comparison of this insertion strategy with conventional amide synthesis demonstrates the synthetic advantages of this new protocol.
A new amide bond activation paradigm through amino acid insertion enabled by two tandem intramolecular rearrangements is reported. This strategy only requires stable and readily available amide and amino acid as the starting materials, which does not need any pre‐functionalization as well as the isolation of reaction intermediates.
Direct dehydrogenative synthesis of α,β-unsaturated secondary amides still represents an elusive transformation. Herein we describe a palladium-catalyzed redox-neutral desaturation to prepare ...α,β-conjugated secondary amides. Without external oxidants, this approach relies on the N–O bond cleavage as the driving force to achieve formal dehydrogenation. Complementary to known protocols, this transformation is enabled by the unique reactivity of hydroxamate, thereby representing a novel strategy to accomplish carbonyl desaturation. Desired conjugated secondary amides can be efficiently synthesized in the presence of more reactive esters and even ketones, thus providing a solution to the long-standing issue of α,β-unsaturated secondary amides via C–C desaturation.
