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

Novák, Petr; Pohl, Radek; Kotora, Martin; Hocek, Michal

doi:10.1021/ol060454m

Cited by 54 publications

(16 citation statements)

References 57 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…These values are comparable to the 2.102(2) Å in (h 5 6 to the 2.06(5) Å in (h 5 -C 5 H 5 )Co(S 2 C 2 B 10 H 10 ), 7 and to the 2.154(9) Å in (h 5 -C 9 H 6 )(C 3 H 7 )(PMe 3 ) 2 CoI. 8 The average Ni-C ring distances of 2.145(6) Å in 5, 2.17 ± 0.01 Å in 7, and 2.131(3) Å in 8 are very close to each other.…”

Section: Synthesis and Structuresupporting

confidence: 79%

“…4f It has been documented that the Co and Ni complexes show some common features with the Ru ones in [2+2+2] cyclotrimerization of alkynes and C-C coupling reactions. 5 Connected to this and to understand the similarities and differences among late transition-metal complexes with linked cyclopentadienyl-carboranyl ligands, we extended our research to include cobalt and nickel metals. We report herein the synthesis, structure, and reactivity of Co and Ni complexes bearing carbon-linked cyclopentadienyl/indenyl-carboranyl ligands.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Synthesis, structural characterization, and reactivity of late transition-metal complexes bearing linked cyclopentadienyl–carboranyl ligands

et al. 2012

View full text Add to dashboard Cite

Late transition-metal complexes bearing linked cyclopentadienyl/indenyl-carboranyl ligands were synthesized and their reactivities were examined. Reaction of Li2[Me2C(L)(C2B10H10)] (L = C5H4, C9H6, Me2NCH2CH2C5H3) with MCl2(PPh3)2 in Et2O afforded [h 5 :s-Me2C(C5H4)(C2B10H10)]M(PPh3) (M = Co (4), Ni (5)), [h 5 :s-Me2C(C9H6)(C2B10H10)]M(PPh3) (M = Co (6), Ni (7)), and [h 5 :s-Me2C(Me2NCH2CH2C5H3)(C2B10H10)]Ni(PPh3) (8). Treatment of 4 or 5 with 2,6-dimethylphenylisocyanide, N-heterocyclic carbene (NHC), PCy3, or 1,2-bis(diphenylphosphino)ethane (dppe) gave the corresponding PPh3 displacement complexes [h 5 :s-Me2C(C5H4)(C2B10H10)]M(2,6-Me2C6H3NC) (M = Co (9), Ni (10)), [h 5 :s-Me2C(C5H4)(C2B10H10)]M[1,3-(2,6-i-Pr2C6H3)2C3N2H2] (M = Co (11), Ni (12)), [h 5 :s-Me2C(C5H4)(C2B10H10)]Ni(PCy3) (13), or {[h 5 :s-Me2C(C5H4)(C2B10H10)]Co}2(dppe) (14), respectively. These complexes were characterized by various spectroscopic techniques and elemental analyses. The molecular structures of 4-14 were further confirmed by singlecrystal X-ray analyses.

show abstract

Section: Synthesis and Structuresupporting

confidence: 79%

Section: Introductionmentioning

confidence: 99%

Synthesis, structural characterization, and reactivity of late transition-metal complexes bearing linked cyclopentadienyl–carboranyl ligands

et al. 2012

View full text Add to dashboard Cite

show abstract

“…[27] Recently, Kotora, Hocek, and co-workers reported the catalytic [2 + 2 + 2] cyclotrimerization of a,w-diynes with C-ethynyldeoxyriboside under mild reaction conditions to form variously substituted C-aryldeoxyriboside derivatives (Scheme 16). [28] Several transition metal catalysts such as Rh, Ni, Ru, and Co complexes were utilized for these reactions. Wilkinsons catalyst [RhClA C H T U N G T R E N N U N G (PPh 3 ) 3 ] afforded optimum yields for variously substituted a,wdiynes.…”

Section: Synthesis Of Substituted Benzene Derivativesmentioning

confidence: 99%

[2+2+2] Cycloaddition Reactions Catalyzed by Transition Metal Complexes

2006

View full text Add to dashboard Cite

Recent progress in the synthesis of benzene and 1,3-cyclohexadiene derivatives, and heterocyclic compounds such as pyridines, pyridones, pyrans, pyrimidine diones, etc, has been reviewed. The general mechanistic aspects of the [2 + 2 + 2] cycloaddition reaction are discussed. The asymmetric variants of these reactions are also discussed along with the proposed models of asymmetric induction. Keywords: arenes; catalysis; cycloaddition; heterocycles; metallacycles; transition metals IntroductionThe significance and increasing popularity of [2 + 2 + 2] cycloaddition reactions is evident from the number of reviews that have recently appeared in the literature. [1][2][3] The [2 + 2 + 2] cycloaddition reaction is remarkable in terms of its ability to utilize various unsaturated substrates such as alkynes, diynes, alkenes, imines, isocyanates, isothiocyanates, and CO 2 in the synthesis of a broad variety of highly substituted cyclic molecules such as benzenes, pyridines, pyridones, 1,3-cyclohexadienes, pyrones, thiopyridones and cyclohexanes. Multisubstituted benzenes and pyridines have traditionally been synthesized by aromatic electrophilic substitution (AES) reactions and a variety of metal-mediated coupling reactions. Although, these reactions are extremely efficient, they generally involve multistep syntheses. The application of AES reactions in the synthesis of polysubstituted aromatic rings is limited by the effect of the substituent groups and, hence, it may be very difficult or even impossible to add various functionalities at a specific position on the aromatic ring. On the other hand, [2 + 2 + 2] cycloaddition reactions are extremely atom-efficient and involve the formation of several C À C bonds in a single step. Another important feature of the [2 + 2 + 2] cycloaddition reaction is tolerance of a myriad of functional groups such as alcohols, amines, alkenes, ethers, esters, halogens, and nitriles. Moreover, the availability of numerous catalytic systems that have Adv. Synth. Catal. 2006, 348, 2307 -2327 2006 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim 2307 REVIEWS been efficient in tedious syntheses highlights the applicability of the [2 + 2 + 2] cycloaddition reaction. These are important requirements for the [2 + 2 + 2] cycloaddition reaction to become a universal synthetic tool for the synthesis of benzene, pyridine, and other cyclic derivatives. An important problem with the [2 + 2 + 2] cycloaddition reaction is the lack of chemoand regioselectivity observed in earlier reported reactions. However, significant effort has been focused on attaining a high degree of chemo-, regio-and even enantioselectivity with considerable success as evident from recent reports. Excellent reviews on [2 + 2 + 2] cycloaddition reactions are available. Kotha and co-workers have reviewed the synthesis of benzene derivatives by the cyclotrimerization of three alkyne functionalities utilizing transition metal systems as catalysts.[1] Their review is divided into: (a) intermolecular reactionsin which the three pi (alkyn...

show abstract

“…This type of transition metal complex-catalyzed [2 þ 2 þ 2] cyclotrimerization of a,o-diynes was applied in the preparation of anomerically pure C-aryldeoxyribosides with C-ethynyldeoxyriboside under simple and mild reaction conditions. 29 and Ni complexes proved to be effective for catalyzing the reaction; the best results were obtained with the stable and easy to handle Wilkinson's catalyst [Rh(PPh 3 ) 3 Cl]. From a synthetic point of view, the advantages of this strategy are the modular approach with regard to structural variety of the a,o-diynes, the functional group compatibility of the transition metal catalysis with a wide variety of functional groups in the reactants and an easily removable p-toluoyl protective group in the deoxyriboside.…”

Section: Cobalt-catalyzed Heterocycle Synthesismentioning

confidence: 99%

CHAPTER 5. Cobalt-Catalyzed Heterocycle Synthesis

2014

Catalysis Series

View full text Add to dashboard Cite

Cobalt has the chemical configuration [Ar]4s 2 3d 7 and has oxidation states Co(II) and Co(III). Cobalt has many applications in a wide range of areas. In materials, cobalt is primarily used as the metal, for example, in the preparation of magnetic, wear-resistant and high-strength alloys. In biology, cobalt is the active center of coenzymes called cobalamins, the most common example of which is vitamin B 12 . As such, it is an essential trace dietary mineral for all animals. Cobalt in inorganic form is also an active nutrient for bacteria, algae and fungi. In chemistry, various cobalt compounds are used as oxidation catalysts in chemical reactions. Cobalt acetate is used for the conversion of xylene to terephthalic acid, the precursor to the bulk polymer poly(ethylene terephthalate). Typical catalysts are the cobalt carboxylates (known as cobalt soaps). They are also used in paints, varnishes and inks as 'drying agents' through the oxidation of drying oils. The same carboxylates are also used to improve the adhesion of steel to rubber in steel-belted radial tires. Cobalt-based catalysts are also important in reactions involving carbon monoxide. In this chapter, the applications of cobalt catalysts in the synthesis of heterocycles is discussed. Five-Membered HeterocyclesIn 1986, Pattenden and co-workers reported a cobalt-promoted oxidative freeradical cyclization of alkyl bromides, 1 by which functionalized butyrolactones were selectively formed in good yields. In 1990, a convenient method for the stereoselective preparation of trans-2-hydroxymethyltetrahydrofurans by the oxidative cyclization of 5-hydroxy-1-alkenes was developed by Inoki and Mukaiyama. 2 They used bis(1-morpholinocarbamoyl-4,4-dimethyl-1,3-pentanedionato)cobalt(II) [Co(modp) 2 ] as the catalyst with molecular oxygen as the RSC Catalysis Series No.

show abstract

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

Cited by 54 publications

References 57 publications

Synthesis, structural characterization, and reactivity of late transition-metal complexes bearing linked cyclopentadienyl–carboranyl ligands

Synthesis, structural characterization, and reactivity of late transition-metal complexes bearing linked cyclopentadienyl–carboranyl ligands

[2+2+2] Cycloaddition Reactions Catalyzed by Transition Metal Complexes

CHAPTER 5. Cobalt-Catalyzed Heterocycle Synthesis

Contact Info

Product

Resources

About