共查询到20条相似文献,搜索用时 15 毫秒
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Bastian Milde Andreas Reding Finn J. Geffers Prof. Dr. Peter G. Jones Prof. Dr. Daniel B. Werz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(41):14544-14547
An intramolecular Pd‐catalyzed trans‐dicarbofunctionalization of internal alkynes using aryl bromides and aryl stannanes is presented. Tetrasubstituted double bonds embedded in an oligocyclic ring system are obtained in a regio‐ and diastereoselective fashion. The transformation features a broad substrate scope and functional‐group tolerance. 相似文献
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Formal anti‐Carbopalladation Reactions of Non‐Activated Alkynes: Requirements,Mechanistic Insights,and Applications 下载免费PDF全文
M.Sc. Martin Pawliczek Dr. Tobias F. Schneider Dr. Christian Maaß Prof. Dr. Dietmar Stalke Prof. Dr. Daniel B. Werz 《Angewandte Chemie (International ed. in English)》2015,54(13):4119-4123
Formal anti‐carbopalladation reactions of C? C triple bonds are uncommon, but highly useful transformations. Alkynes can be designed to give anti‐carbopalladation products. Prerequisite is the exclusion of other reaction pathways to provoke the cis–trans isomerization of the syn‐carbopalladation intermediate. Detailed mechanistic studies of this crucial step by experimental and computational means were performed. Application of an intramolecular version for the synthesis of oligocyclic compounds and substituted dibenzofurans is also described. 相似文献
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Alexander Düfert Daniel B. Werz 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(47):16718-16732
Alkynes are one of the most versatile functional groups as synthetic handles. They allow for a direct access to partially or fully substituted alkenes through difunctionalization reactions. A prominently utilized transformation for these sequences is the carbopalladation of alkynes, which can be followed by various termination steps such as aromatizations, dearomatizations, cross‐coupling reactions, or pericyclic processes, amongst others. This Minireview provides an overview of the recent literature published in the field of carbopalladation chemistry, both with a focus on methodology as well as its application in the syntheses of complex molecular scaffolds, natural products, and functional molecules. 相似文献
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trans‐Carbocarbonation of Internal Alkynes through a Formal anti‐Carbopalladation/C−H Activation Cascade 下载免费PDF全文
M. Sc. Andreas Reding Prof. Dr. Peter G. Jones Prof. Dr. Daniel B. Werz 《Angewandte Chemie (International ed. in English)》2018,57(33):10610-10614
An intramolecular Pd‐catalyzed cascade reaction is presented that consists of a formal anti‐carbopalladation of a C?C triple bond followed by C?H activation. As a result, oligocyclic ring systems with an embedded tetrasubstituted double bond are formed. The key to success in affording the trans geometry of the emerging double bond are alkyne units with residues that must not undergo β‐hydride elimination (e.g., t‐butyl or silyl groups). Silyl groups proved to be a perfect handle to further convert the tetrasubstituted alkenes. The evaluation of kinetic data with a deuterium‐labeled compound and X‐ray analyses of trapped intermediates provided additional insight into the catalytic cycle. 相似文献
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Lionel Joucla Florence Popowycz Olivier Lozach Laurent Meijer Benoît Joseph 《Helvetica chimica acta》2007,90(4):753-763
The syntheses of paullone ( 1a ) and three paullone derivatives, including a sulfur analogue ( 2a ), a tricyclic derivative ( 2b ), and a ring‐enlarged variant ( 2c ), are described, Pd‐catalyzed intramolecular Heck reaction being the key step. The kinase‐inhibitory properties of the novel paullone analogues were investigated. 相似文献
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π‐Helicenes Truncated to a Minimum: Access Through a Domino Approach Involving Multiple Carbopalladations and a Stille Coupling 下载免费PDF全文
M.Sc. Bastian Milde Dr. Markus Leibeling M.Sc. Martin Pawliczek Prof. Dr. Jörg Grunenberg Prof. Dr. Peter G. Jones Prof. Dr. Daniel B. Werz 《Angewandte Chemie (International ed. in English)》2015,54(4):1331-1335
A novel type of π‐helicenes is reported, in which the π‐system is truncated to an all‐s‐cis all‐Z oligoene chain. A domino sequence was developed, consisting of up to four consecutive carbopalladation reactions and a terminal Stille cross‐coupling, to generate these entities in one step from the respective linear oligoynes. Despite the minimal π‐system, very high optical rotation values were encountered for the single enantiomers. X‐ray crystallography confirmed their screw‐shaped structure. 相似文献
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Claire Kammerer Guillaume Prestat Dr. David Madec Dr. Giovanni Poli Prof. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2009,15(17):4224-4227
Free to decide : Various 4‐(α‐styryl) γ‐lactams are synthesized in 61–88 % yield by a phosphine‐free palladium‐catalyzed carbopalladation/allylic alkylation domino sequence (see scheme). The cyclization is totally regio‐ and diastereoselective in favor of the 3,4‐trans‐disubstituted γ‐lactam. The process is successfully applied to the synthesis of a new aza analogue of the naturally occurring lignan (+)‐oxo‐parabenzlactone.
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Dr. Rosana Álvarez Claudio Martínez Youssef Madich J. Gabriel Denis Dr. José M. Aurrecoechea Prof. Dr. Ángel R. de Lera 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(42):12746-12753
Structurally diverse C3‐alkenylbenzofurans, C3‐alkenylindoles, and C4‐alkenylisoquinolones are efficiently prepared by using consecutive Sonogashira and cascade Pd‐catalyzed heterocyclization/oxidative Heck couplings from readily available ortho‐iodosubstituted phenol, aniline, and benzamide substrates, alkynes, and functionalized olefins. The cyclization of O‐ and N‐heteronucleophiles follows regioselective 5‐endo‐dig‐ or 6‐endo‐dig‐cyclization modes, whereas the subsequent Heck‐type coupling with both mono‐ and disubstituted olefins takes place stereoselectively with exclusive formation of the E isomers in most cases. 相似文献
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Pd0‐Catalyzed Intramolecular α‐Arylation of Sulfones: Domino Reactions in the Synthesis of Functionalized Tetrahydroisoquinolines 下载免费PDF全文
Prof.Dr. Daniel Solé Ferran Pérez‐Janer Dr. Raffaella Mancuso 《Chemistry (Weinheim an der Bergstrasse, Germany)》2015,21(12):4580-4584
A new strategy for the synthesis of tetrahydroisoquinolines based on the Pd0‐catalyzed intramolecular α‐arylation of sulfones is reported. The combination of this Pd‐catalyzed reaction with intermolecular Michael and aza‐Michael reactions allows the development of two‐ and three‐step domino processes to synthesize diversely functionalized scaffolds from readily available starting materials. 相似文献
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Dr. Upendra K. Sharma Dr. Brajendra K. Singh Prof.Dr. Erik V. Van der Eycken 《Chemistry (Weinheim an der Bergstrasse, Germany)》2016,22(2):481-485
A microwave‐assisted highly efficient intermolecular domino carbopalladation/C?H functionalization sequence has been developed to access bis‐heteroaryl frameworks in a single operation. The reaction involves carbopalladation of the halogenated acrylamides or phenylpropiolamides by the Pd(0) catalysis, followed by the direct (hetero)arylation to give products with good to excellent yields. The synthetic utility of this method was also extended towards the application of the Ugi‐adduct as the starting material. 相似文献
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Egle M. Beccalli Prof. Elena Borsini Stefano Brenna Dr. Simona Galli Dr. Micol Rigamonti Gianluigi Broggini Dr. 《Chemistry (Weinheim an der Bergstrasse, Germany)》2010,16(5):1670-1678
The isolation of σ‐alkylpalladium Heck intermediates, possible when β‐hydride elimination is inhibited, is a rather rare event. Performing intramolecular Heck reactions on N‐allyl‐2‐halobenzylamines in the presence of [Pd(PPh3)4], we isolated and characterized a series of stable bridged palladacycles containing an iodine or bromine atom on the palladium atom. Indolyl substrates were also tested for isolation of the corresponding complexes. X‐ray crystallographic analysis of one of the indolyl derivatives revealed the presence of a five‐membered palladacycle with the metal center bearing a PPh3 ligand and an iodine atom in a cis position with respect to the nitrogen atom. The stability of the σ‐alkylpalladium complexes is probably a consequence of the strong constraint resulting from the bridged junction that hampers the cisoid conformation essential for β‐hydride elimination. Subsequently, the thus obtained bridged five‐membered palladacycles were proven to be effective precatalysts in Heck reactions as well as in cross‐coupling processes such as Suzuki and Stille reactions. 相似文献