The direct difunctionalization of alkenes, a cheap and abundant feedstock, represents one of the most attractive strategies for increasing molecular complexity in synthetic organic chemistry. In ...contrast with the 1,2‐difunctionalization of alkenes, recent advances showcase alkene 1,n‐difunctionalizations (n≠2) involving metal migration is an emerging and rapidly growing area of research. This promising strategy not only opens a novel avenue for future development of alkene transformations, but also significantly expands upon the bond disconnections available in modern organic synthesis. This Minireview summarizes recent progress in the migratory difunctionalization of alkenes, with an emphasis on the driving force for metal migration.
Driving force: The difunctionalization of alkenes involving metal migration provides access to a new class of products that are not readily synthesized by other methods. This Minireview summarizes recent advances in the field, with an emphasis on the driving force for metal migration.
The Catellani reaction is known as a powerful strategy for the expeditious synthesis of highly substituted arenes and benzo‐fused rings, which are usually difficult to access through traditional ...cross‐coupling strategies. It utilizes the synergistic interplay of palladium and norbornene catalysis to facilitate sequential ortho C−H functionalization and ipso termination of aryl halides in a single operation. In classical Catellani‐type reactions, aryl halides are mainly used as the substrates, and a Pd0 catalyst is required to initiate the reaction. Nevertheless, recent advances showcase that Catellani‐type reactions can also be initiated by a PdII catalyst with different starting materials instead of aryl halides via different reaction mechanisms and under different conditions. This emerging concept of PdII/norbornene cooperative catalysis has significantly advanced Catellani‐type reactions, thus enabling future developments of this field. In this Minireview, PdII‐initiated Catellani‐type reactions and their application in the synthesis of bioactive molecules are summarized.
Cooperative solutions: Palladium(II)‐initiated norbornene (NBE)‐mediated cooperative catalysis has enabled significant developments of the Catellani reaction. These advances and their application in the synthesis of bioactive molecules are summarized in this Minireview.
Chiral tetrahydrocarbazoles (THCs) are prevalent in numerous natural indole alkaloids as well as synthetic pharmaceuticals, and exhibit a broad spectrum of bioactivities. As such, the development of ...efficient synthetic methodologies for the synthesis of chiral THCs is of substantial interest. The advent of asymmetric catalysis provides a powerful platform to assemble chiral THC motifs and great efforts have been devoted to this field over the past decades. In this feature article, we summarise recent advances in catalytic asymmetric synthesis of THCs, with particular emphases on reaction types and reaction mechanism.
Reported is a modular one‐step three‐component synthesis of tetrahydroisoquinolines using a Catellani strategy. This process exploits aziridines as the alkylating reagents, through ...palladium/norbornene cooperative catalysis, to enable a Catellani/Heck/aza‐Michael addition cascade. This mild, chemoselective, and scalable protocol has broad substrate scope (43 examples, up to 90 % yield). The most striking feature of this protocol is the excellent regioselectivity and diastereoselectivity observed for 2‐alkyl‐ and 2‐aryl‐substituted aziridines to access 1,3‐cis‐substituted and 1,4‐cis‐substituted tetrahydroisoquinolines, respectively. Moreover, this is a versatile process with high step and atom economy.
A modular synthesis of tetrahydroisoquinolines was developed. Aziridines act as the alkylating reagents to enable a Catellani/Heck/aza‐Michael addition cascade by palladium/norbornene (NBE) cooperative catalysis. This mild, chemoselective, and scalable protocol is compatible with a wide range of readily available aryl iodides, aziridines, and olefins. Excellent regio‐ and diastereoselectivities are observed for 1,3‐cis‐substituted and 1,4‐cis‐substituted tetrahydroisoquinolines.
We report a cooperative catalytic system comprising a PdII complex, XPhos, and the potassium salt of 5‐norbornene‐2‐carboxylic acid that enables the use of epoxides as alkylating reagents in the ...Catellani reaction, thereby expanding the existing paradigm of this powerful transformation. The potassium salt of inexpensive 5‐norbornene‐2‐carboxylic acid acts as both mediator and base in the process. This mild, chemoselective, scalable, and atom‐economical protocol is compatible with a wide variety of readily available functionalized aryl iodides and epoxides, as well as terminating olefins. The resulting products undergo facile oxa‐Michael addition to furnish ubiquitous isochroman scaffolds.
A little cooperation can go a long way: A cooperative catalytic system comprising a PdII/XPhos complex and the potassium salt of 5‐norbornene‐2‐carboxylic acid, which serves dual roles as a mediator and a base, enabled the use of epoxides as alkylating reagents in the Catellani reaction (see scheme). The products could also undergo oxa‐Michael addition to furnish valuable isochroman scaffolds.
The Catellani reaction is a powerful strategy that allows the expeditious synthesis of highly substituted arenes, which are not easily accessible through traditional transition‐metal‐catalyzed ...cross‐coupling reactions. This reaction utilizes the synergistic interplay of palladium and norbornene catalysis to facilitate sequential ortho‐C−H functionalization and ipso termination of aryl iodides in a single operation. Since pioneering work by the group of Catellani in 1997, and later by the group of Lautens, this chemistry has attracted considerable attention from the synthetic chemistry community. Dramatic progress has been made by a number of groups in the past two decades. In this Minireview, the alkylating reagents employed in this intriguing reaction and the corresponding applications in organic synthesis are summarized; thus complementing existing reviews to inspire future developments.
Changing conventions: The Catellani reaction, such as depicted, is a powerful strategy that allows the expeditious synthesis of highly substituted arenes, which are not easily accessible through traditional transition‐metal‐catalyzed cross‐coupling reactions (NBE=norbornene). This review highlights the alkylating reagents employed in these reactions and related applications in organic synthesis.
A Concise Total Synthesis of (−)‐Berkelic Acid Cheng, Hong‐Gang; Yang, Zhenjie; Chen, Ruiming ...
Angewandte Chemie International Edition,
March 1, 2021, Letnik:
60, Številka:
10
Journal Article
Recenzirano
Reported here is a concise total synthesis of (−)‐berkelic acid in eight linear steps. This synthesis features a Catellani reaction/oxa‐Michael cascade for the construction of the isochroman ...scaffold, a one‐pot deprotection/spiroacetalization operation for the formation of the tetracyclic core structure, and a late‐stage Ni‐catalyzed reductive coupling for the introduction of the lateral chain. Notably, four stereocenters are established from a single existing chiral center with excellent stereocontrol during the deprotection/spiroacetalization process. Stereocontrol of the intriguing deprotection/spiroacetalization process is supported by DFT calculations.
A concise total synthesis of (−)‐berkelic acid in eight linear steps was developed. This synthesis features a Catellani reaction/oxa‐Michael cascade for the construction of the isochroman scaffold, a one‐pot deprotection/spiroacetalization operation for the formation of tetracyclic core structure, and a late‐stage Ni‐catalyzed reductive coupling for the introduction of the lateral chain.
1,3‐trans‐Disubstituted tetrahydroisoquinoline (THIQ) is a common heterocyclic structural unit of naphthylisoquinoline alkaloids. The assembly of this structural unit is not trivial, which ...constitutes a substantial challenge in the total synthesis of naphthylisoquinoline alkaloids and related pharmaceuticals. Herein, we report a modular and convergent method for the rapid assembly of 1,3‐trans‐disubstituted THIQ frameworks through a three‐component Catellani reaction and a AuI‐catalyzed cyclization/reduction cascade. With widely available simple aryl iodides, aziridines and (triisopropylsilyl)acetylene as the building blocks, this method paves a practical way for the diversity‐oriented synthesis of 1,3‐trans‐disubstituted THIQs. Based on this new method, concise syntheses of an analogue of the new drug mevidalen and four naphthylisoquinoline alkaloids have been accomplished, demonstrating the broad synthetic utility of this approach.
A modular and step‐economical approach based on a three‐component Catellani reaction and a gold(I)‐catalyzed cyclization/reduction cascade has been established for the diversity‐oriented synthesis of 1,3‐trans‐disubstituted tetrahydroisoquinolines. This synthetic strategy enabled concise syntheses of an analogue of the new drug mevidalen as well as four naphthylisoquinoline alkaloids.
Reported is a novel palladium(II)‐initiated Catellani‐type reaction that utilizes widely accessible aryl boronic acids as the substrates instead of aryl halides, thereby greatly expanding the ...existing scope of this powerful transformation. This borono‐Catellani reaction was promoted by cooperative catalysis between Pd(OAc)2 and the inexpensive 5‐norbornene‐2‐carbonitrile. Practicality is the striking feature of the reaction: it is run open to air at ambient temperature and no phosphine ligand is needed. This mild, chemoselective, and scalable protocol is compatible with a large range of readily available functionalized aryl boronic acids and bromides, as well as terminating olefins (50 examples, 39–97 % yields). Moreover, the orthogonal reactivity between the borono‐Catellani and classical Catellani reaction was demonstrated. This work is expected to open new avenues for developing novel Catellani‐type reactions.
Put a B on it: A PdII‐initiated borono‐Catellani reaction using readily available aryl boronic acids as the substrates, instead of aryl halides, was developed. The reaction is promoted by Pd(OAc)2 and 5‐norbornene‐2‐carbonitrile, and is run open to air at ambient temperature without a phosphine ligand. This chemoselective protocol is compatible with a range of functionalized aryl boronic acids and bromides, as well as terminating olefins.
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