[4 + 2] Annulation of Donor–Acceptor Cyclopropanes with Acetylenes Using 1,2-Zwitterionic Reactivity

Новиков, Роман А.; Tarasova, Anna V.; Denisov, Dmitry A.; Борисов, Д. И.; Королев, В. А.; Timofeev, Vladimir P.; Tomilov, Yu. V.

doi:10.1021/acs.joc.7b00209

Cited by 59 publications

(18 citation statements)

References 56 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Consequently, the β , γ ‐unsaturated ester alkene 4 could be converted to the corresponding α , β ‐unsaturated ester 7 , and thus form the 9,10‐dihydrophenanthrene 3 a . In the strongly acidic conditions, a stable cation 8 was generated after release of diethyl malonate, and converted to phenanthrene ( 5 ) via β ‐H elimination, which is similar to that proposed in previous reports …”

Section: Methodssupporting

confidence: 87%

See 1 more Smart Citation

Intramolecular Arylative Ring Opening of Donor‐Acceptor Cyclopropanes in the Presence of Triflic Acid: Synthesis of 9H‐Fluorenes and 9,10‐Dihydrophenanthrenes

Wang

Zhao

et al. 2019

Asian J Org Chem

View full text Add to dashboard Cite

A unique intramolecular arylative ring opening of 2-biaryl substituted donor-acceptor cyclopropanes in the presence of triflic acid was found, furnishing 9H-fluorenes and 9,10-dihydrophenanthrenes. Chemoselectivity between both products is achieved by modification of the solvent, temperature, and amount of triflic acid. Representative large-scale experiments were also carried out successfully with good outcomes.Donor-acceptor cyclopropanes (DACs) are versatile building blocks in organic synthesis for assembling various classes of compounds. The typical cycloaddition of DACs with unsaturated compounds can be used to construct five-, six-, and sevenmembered carbocyclic and heterocyclic compounds. [1] The nucleophilic ring opening of DACs with a variety of heteroatomatic and carbon nucleophiles is demonstrated as a flexible tool to create CÀ X bonds. [1b-c,f-h,j,2] DACs, particularly 2-aryl cyclopropane-1,1-dicarboxylates, have high ring strain, and the corresponding cation and anion intermediates formed by heterolysis of the cyclopropane ring are relatively stable. As a result, DACs usually serve as 1,3-zwitterionic intermediates under the catalysis of Lewis acid or Brønsted acid, and proceed by nucleophilic addition at their C1 position (Scheme 1a). Recently, generation of 1,2-zwitterions from DACs under specified conditions was explored, [3] and some C2-addition reactions were reported (Scheme 1a). [4] Arylative ring opening of 2-aryl substituted DACs forms substituted diarylmethanes by C1-addition (Scheme 1b). Several arylative nucleophiles have been explored, including indoles, [5] benzo[b]furan, [6] electron-rich arenes, [7] polycyclic aromatic species, [7b,g,8] and arylboronic acids bearing electron-donating groups. [9] All of the arylative reactants are relatively reactive nucleophiles, and most of the arylation reactions are intermolecular. [10] However, it is well known that intramolecular reaction can be relatively easily achieved. Hence we assumed that the intramolecular arylative ring opening of DACs with less reactive arenes was possible. The intramolecular reactions would enlarge the limited range of nucleophiles in this type of reaction.With this perspective, we decided to test the intramolecular arylative ring opening of 2-(2'-biphenyl) cyclopropane-1,1dicarboxylate (1 a) to assess the nucleophilicity of the general aryl group (Table 1). When 1 a was treated with one equivalent of triflic acid (TfOH) at room temperature, the C1-addition product, 9H-fluorene 2 a, was indeed formed, but surprisingly, the C2-addition product, 9,10-dihydrophenanthrene 3 a, was obtained as the major product (entry 1). The proportion of 2 a increased with the increasing temperature (entry 2) or loading amount of TfOH (entry 3-5). An excellent yield (95%) of pure 2 a could be obtained when excess TfOH was used (entry 5). On the contrary, lowering the temperature or loading amount of [a]

show abstract

Section: Methodssupporting

confidence: 87%

“…4). According to the previous reports, 5 probably came from 3 a via elimination of diethyl malonate . However, the yield of 5 was much higher than that of 3 a in eq.…”

Section: Methodsmentioning

confidence: 86%

Intramolecular Arylative Ring Opening of Donor‐Acceptor Cyclopropanes in the Presence of Triflic Acid: Synthesis of 9H‐Fluorenes and 9,10‐Dihydrophenanthrenes

Wang

Zhao

et al. 2019

Asian J Org Chem

View full text Add to dashboard Cite

show abstract

“…for similar reactions of 1,3‐zwitterions with acetylenes). However, [4+2] annulation was efficiently implemented for aryl acetylenes only . Alkyl acetylenes underwent this reaction very poorly.…”

Section: Methodssupporting

confidence: 82%

“…[4+2] annulation (Scheme ) is the most typical reaction of ACDCs 1 with acetylenes and occurs through the generation of 1,2‐zwitterionic intermediates 2 (see also Ref. for similar reactions of 1,3‐zwitterions with acetylenes).…”

Section: Methodsmentioning

confidence: 99%

See 1 more Smart Citation

Three‐Component Gallium(III)‐Promoted Addition of Halide Anions and Acetylenes to Donor–Acceptor Cyclopropanes

et al. 2018

Self Cite

View full text Add to dashboard Cite

A new strategy for the three-component addition of halide anions and acetylenes to donor-acceptor cyclopropanes (DACs) is presented. This reaction, which occurs with high E selectivity, is promoted by gallium(III) salts and based on the 1,2-zwitterionic reactivity of DACs. It opens up a new group of processes involving DACs. The reaction occurs readily with a broad range of substrates and is tolerant of various functional groups. This methodology makes it possible to assemble highly functionalized vinyl halides, which are very convenient building blocks in organic synthesis. A possible mechanism of this reaction and its stereochemical aspects are discussed in detail.

show abstract

Cycloaddition and Annulation Reactions of Donor–Acceptor Cyclopropanes

Novikov,

Borisov,,

Tomilov

2024

Donor Acceptor Cyclopropanes in Organic Synthesis

View full text Add to dashboard Cite

[4 + 2] Annulation of Donor–Acceptor Cyclopropanes with Acetylenes Using 1,2-Zwitterionic Reactivity

Cited by 59 publications

References 56 publications

Intramolecular Arylative Ring Opening of Donor‐Acceptor Cyclopropanes in the Presence of Triflic Acid: Synthesis of 9H‐Fluorenes and 9,10‐Dihydrophenanthrenes

Intramolecular Arylative Ring Opening of Donor‐Acceptor Cyclopropanes in the Presence of Triflic Acid: Synthesis of 9H‐Fluorenes and 9,10‐Dihydrophenanthrenes

Three‐Component Gallium(III)‐Promoted Addition of Halide Anions and Acetylenes to Donor–Acceptor Cyclopropanes

Cycloaddition and Annulation Reactions of Donor–Acceptor Cyclopropanes

Contact Info

Product

Resources

About