[2+2+2]-Co-cyclotrimerization 6-alkynylpurines with diynes: a method for preparation of 6-arylpurines

Turek, Pavel; Kotora, Martin; Hocek, Michal; Cı́sařová, Ivana

doi:10.1016/s0040-4039(02)02643-6

Cited by 30 publications

(7 citation statements)

References 24 publications

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“…Nonetheless, in cases where the heterocyclic ring was formed, such as in 3 β e and 3 β f (entries 5 and 6), the yields were rather low. Although it has recently been shown that Co(PPh 3 ) 3 Br was very active for cyclotrimerization of various alkynes and especially dipropargyl ether, 18b, the reaction of 1 β with 2a and 2f afforded the corresponding products 3 β a and 3 β f in only 23 and 25% yields (entry 5 and 6), respectively.…”

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confidence: 99%

Synthesis of C-Aryldeoxyribosides by [2 + 2 + 2]-Cyclotrimerization Catalyzed by Rh, Ni, Co, and Ru Complexes

et al. 2006

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[reaction: see text] A novel approach to the synthesis of functionalized C-nucleosides was developed. Cyclotrimerization of C-alkynyldeoxyriboside with a variety of substituted 1,6-heptadiynes to the corresponding C-aryldeoxyribosides was catalyzed by various transition metal complexes (Rh, Ir, Co, Ru, and Ni). The most general catalyst proved to be RhCl(PPh(3))(3), which could catalyze most of the cyclotrimerizations in high yields (52-95%).

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Synthesis of C-Aryldeoxyribosides by [2 + 2 + 2]-Cyclotrimerization Catalyzed by Rh, Ni, Co, and Ru Complexes

et al. 2006

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“…The Sonogashira reaction is valuable for the synthesis of 6-alkynylpurine nucleosides, which serve as intermediates for the preparation of highly substituted 6-arylpurine nucleosides that are not readily accessible by standard coupling reactions . No cross-coupling product was detected upon treatment of the 6-chloro analogue 3b (Scheme ) with 1-hexyne/Pd(PPh 3 ) 4 /CuI/TEA for 10 h at ambient temperature.…”

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S_NAr Iodination of 6-Chloropurine Nucleosides: Aromatic Finkelstein Reactions at Temperatures Below −40 °C¹

2004

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Mesitoyl or toluoyl esters of inosine and 2'-deoxyinosine were deoxychlorinated at C6 to give the crystalline 6-chloropurine nucleoside derivatives, which underwent quantitative conversion to the 6-iodo analogues with NaI/TFA/butanone at -50 to -40 degrees C. The 6-iodo compounds were efficient substrates for SNAr, Sonogashira, and Suzuki-Miyaura reactions, in contrast with the 6-chloro analogues, and gave good to high yields of C-N and C-C coupled products.

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“…In 2002, Sugihara and co-workers reported the first synthetic route to phthalans by Co-catalyzed [2+2+2] cyclotrimerization reactions, performed with methylidynetricobalt nonacarbonyl (2 mol%) in refluxing toluene. 62 Many cobaltbased catalytic systems were then explored, ranging from the most common [Co 2 (CO) 8 ] 63 and [CpCo(CO) 2 ] 64 to phosphine complexes like [CoBr(PPh 3 ) 3 ], 65 [CoI 2 (PPh 3 ) 2 ], 66 and [CoCl(PPh 3 ) 3 ]. 67 Hapke and co-workers described a systematic study by ligand variation on the [CpCo…”

Section: Scheme 19 Tetra-ortho-substituted Axially Chiral Biaryls Viamentioning

confidence: 99%

Cyclization Reactions for the Synthesis of Phthalans and Isoindolines

Albano

Aronica

2018

Synthesis

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Oxygen and nitrogen heterocycles are present in a vast number of natural substrates and biologically active molecules. In particular, phthalan and isoindoline subunits are found in many classes of products such as antibiotics, antioxidants, antimycotics, pigments, and fluorophores. Therefore several procedures dedicated to the construction of these heterocycles have been developed. In this review, a detailed analysis of the literature data regarding the synthesis of these nuclei via cyclization reactions is reported.1 Introduction2 Phthalans2.1 Oxa-Pictet–Spengler Reaction2.2 Garratt–Braverman Cyclization2.3 Diels–Alder and Related Reactions2.4 [2+2+2] Cyclotrimerization of Alkynes2.5 Cycloetherification of ortho-Substituted Aromatics2.6 Tandem Carbonylative Sonogashira Coupling–Cyclization Reactions3 Isoindolines3.1 Amination of Dihalides3.2 Intramolecular Hydroamination3.3 Diels–Alder and Related Reactions3.4 [2+2+2] Cycloaddition Reactions3.5 Tandem Carbonylative Sonogashira Coupling–Cyclization Reactions4 Conclusions

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[2+2+2]-Co-cyclotrimerization 6-alkynylpurines with diynes: a method for preparation of 6-arylpurines

Cited by 30 publications

References 24 publications

Synthesis of C-Aryldeoxyribosides by [2 + 2 + 2]-Cyclotrimerization Catalyzed by Rh, Ni, Co, and Ru Complexes

Synthesis of C-Aryldeoxyribosides by [2 + 2 + 2]-Cyclotrimerization Catalyzed by Rh, Ni, Co, and Ru Complexes

S_NAr Iodination of 6-Chloropurine Nucleosides: Aromatic Finkelstein Reactions at Temperatures Below −40 °C¹

Cyclization Reactions for the Synthesis of Phthalans and Isoindolines

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[2+2+2]-Co-cyclotrimerization 6-alkynylpurines with diynes: a method for preparation of 6-arylpurines

Cited by 30 publications

References 24 publications

Synthesis of C-Aryldeoxyribosides by [2 + 2 + 2]-Cyclotrimerization Catalyzed by Rh, Ni, Co, and Ru Complexes

Synthesis of C-Aryldeoxyribosides by [2 + 2 + 2]-Cyclotrimerization Catalyzed by Rh, Ni, Co, and Ru Complexes

SNAr Iodination of 6-Chloropurine Nucleosides: Aromatic Finkelstein Reactions at Temperatures Below −40 °C1

Cyclization Reactions for the Synthesis of Phthalans and Isoindolines­

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S_NAr Iodination of 6-Chloropurine Nucleosides: Aromatic Finkelstein Reactions at Temperatures Below −40 °C¹

Cyclization Reactions for the Synthesis of Phthalans and Isoindolines