Synthesis of 4-Arylidenepyrazolones by a Gold-Catalyzed Cyclization/Arylidene Group Transfer Cascade of <i>N</i>-Propioloyl Hydrazones

Ding, Zong‐Cang; Tang, Hai‐Tao; Li, Ren‐Hao; Ju, Lu‐Chuan; Zhan, Zhuang‐Ping

doi:10.1021/acs.joc.5b01366

Cited by 14 publications

(11 citation statements)

References 49 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In these reactions, no external oxidant is needed since no redox cycle operates. A number of chemical functions have been shown to efficiently transfer during the cyclizations of O ‐, N ‐ or S ‐ centered nucleophiles to mostly alkynes electrophiles, such as alkyl, [10] silyl, [11] sulfonyl, [12] arylidene, [13] propargyl [14] or allyl groups [10a,15] . All these reactions raise questions regarding the associative of dissociative nature of the mechanism, which appears to be strongly dependent on the heteroatom and the migratory group.…”

Section: Methodsmentioning

confidence: 99%

Gold‐Catalyzed Carboamination of Allenes by Tertiary Amines Proceeding with Benzylic Group Migration

2021

View full text Add to dashboard Cite

Tertiary amines bearing a benzyl-type group (CH2Ar) undergo Au(I)-catalyzed intramolecular addition to allenes. A formal 1,3-transfer of the CH2Ar group takes place during the cyclization. As demonstrated by both experimental and DFT studies, these unprecedented intramolecular carboaminations involve two consecutive [3,3] rearrangements via a dearomatized intermediate. Because of the poor stability of the enamine products, protocols were developed to convert them in situ to more stable polycyclic chiral compounds.After almost two decades of intense research, homogeneous gold catalysis has established itself as an inescapable field in organic synthesis. [1],[2] The π-acidic properties Au(I) complexes enable a vast range of catalytic reactions, leading to a huge structural diversity. Among the popular reactivity of these complexes, hydrofunctionalizations of unsaturated substrates hold a salient position. The diversity of nucleophiles combined with various unsaturated electrophilic partners lead to an efficient access to a number of important heterocycles. [3] In most cases, the reactions evolve through a general similar pathway combining 1) activation of the unsaturation, 2) addition of the nucleophile and 3) protodeauration reaction. This strategy was very efficiently applied to hydrofunctionalization [4] of alkynes, [5] allenes [6] or alkenes (Scheme 1, type A). [7] In some reactions though (mainly from alkenes), it is possible to oxidize the intermediate gold species and promote an additional functionalization by a nucleophile resulting most of the time into a formal double heterofunctionalization (Scheme 1, type B). [1h, 8],[9] However, reactions performed with functionalized nucleophiles (no X-H bond), for which the protodeauration step cannot take place, may lead to both cyclization and a transfer of the functional group via intriguing mechanisms (Scheme 1, type C). In these reactions, no external oxidant is needed since no redox cycle operates. A number of chemical functions have been shown to efficiently transfer during the cyclizations of O-, N-or S-centered nucleophiles to mostly alkynes electrophiles, such as alkyl, [10] silyl, [11] arylidene, [12] propargyl [13] or allyl groups. [10a, 14] All these reactions raise questions a) Measured by 1 H NMR. Reactions were performed for 16 h. b) Reaction performed over 4 h. c) Reaction performed over 24 h.As we observed in our previous studies, [17] the enamine nature of product 2d complicates its purification and isolation because of its high reactivity. For this reason, we established two different protocols to directly convert compounds 2d into a stable product (Scheme 4). In a first approach, we directly reduced the enamine resulting from the carboamination to the corresponding amine by addition of NaBH4 and MeOH after completion of the Au(I)-catalyzed reaction. This resulted in the formation of compound 4d as a single diastereoisomer in 73% yield (See the Supporting Information for optimization of the reduction). NOESY studies revealed that compound ...

show abstract

Section: Methodsmentioning

confidence: 99%

Gold‐Catalyzed Carboamination of Allenes by Tertiary Amines Proceeding with Benzylic Group Migration

2021

View full text Add to dashboard Cite

show abstract

“…The reaction of alkynones 71 with 5 mol% IPrAuCl and AgOTf delivered the corresponding cyclic derivatives 72 in good yield via tandem amination and [1,3]-shift ( Scheme 46 ). 60 The reaction worked well with aliphatic as well as aromatic alkynes, except TMS-alkynes. Further, in general it was observed that tosyl/aliphatic amides (R 3 = TMS, alkyl) did not furnish the required products.…”

Section: Intramolecular Carboaminationmentioning

confidence: 93%

1,2-Difunctionalizations of alkynes entailing concomitant C–C and C–N bond-forming carboamination reactions

Nanda

Mallik

2022

RSC Adv.

View full text Add to dashboard Cite

show abstract

“…In 2015, Zhan and coworkers reported a variant of this reaction involving Npropiolylhydrazone 806 as substrates (Scheme 191, part B). 340 Treatment of 806 with the (IPr)AuCl/AgNTf 2 catalytic system in refluxing toluene allowed for a generally efficient conversion into 4-arylidenepyrazolones 807. The same limitations in substitution patterns were observed.…”

Section: Functionalization With N-based Nucleophilesmentioning

confidence: 99%

“…Notably, this process was quite selective toward the formation of the Z -isomer of isoxazolones 802 . In 2015, Zhan and coworkers reported a variant of this reaction involving N -propiolylhydrazone 806 as substrates (Scheme , part B) . Treatment of 806 with the (IPr)AuCl/AgNTf 2 catalytic system in refluxing toluene allowed for a generally efficient conversion into 4-arylidenepyrazolones 807 .…”

Section: Carbon π-Systems With Electron-withdrawing Groupsmentioning

confidence: 99%

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

et al. 2020

View full text Add to dashboard Cite

This review describes the gold-catalyzed reactions of specially activated alkynes, allenes, and alkenes. Such species are characterized by the presence of either electron-donating or electron-withdrawing groups as substituents of the carbon π-system. They are intrinsically polarized, and when compared to their nonspecially activated counterparts can therefore be involved in gold-catalyzed transformations featuring increased regio-, stereo-, and chemoselectivities. The chemistry of specially activated carbon π-systems under homogeneous gold catalysis is extremely rich and varied. The reactivity observed with nonspecially activated unsaturated systems can often be transposed to specially activated ones without loss of efficiency. However, specially activated carbon π-systems also exhibit specific reactivities that cannot be attained with regular substrates. In this family of carbon π-systems, ynamides and their analogs, along with alkynyl carbonyl derivatives, are the classes of substrates that have retained the most attention. This review provides an overview of the chemistry developed with all classes of specially activated carbon π-systems by discussing their general and specific reactivities, presenting and commenting on their gold-catalyzed transformations as well as their applications.

show abstract

Synthesis of 4-Arylidenepyrazolones by a Gold-Catalyzed Cyclization/Arylidene Group Transfer Cascade of N-Propioloyl Hydrazones

Abstract: An efficient gold-catalyzed cyclization/arylidene group transfer cascade reaction of N-propioloyl hydrazones has been developed. This method provides a novel approach for the synthesis of various functionalized 4-arylidenepyrazolones.

Cited by 14 publications

References 49 publications

Gold‐Catalyzed Carboamination of Allenes by Tertiary Amines Proceeding with Benzylic Group Migration

Gold‐Catalyzed Carboamination of Allenes by Tertiary Amines Proceeding with Benzylic Group Migration

1,2-Difunctionalizations of alkynes entailing concomitant C–C and C–N bond-forming carboamination reactions

Gold-Catalyzed Reactions of Specially Activated Alkynes, Allenes, and Alkenes

Contact Info

Product

Resources

About