145198-85-2

Upstream product

• 4083-64-1 Tosyl isocyanate 
• 113495-34-4 3-vinyl-2,6-dioxacyclohexan-1-one 
• 155354-80-6 penta-3,4-dien-1-yl tosylcarbamate 
• 5557-87-9 3,4-pentadiene-1-ol 
• 30332-99-1 penta-3,4-dienoic acid ethyl ester 
• 1201224-03-4 pent-4-enyl (N-p-toluenesulfonyl)carbamate 
• 821-09-0 n-Pent-4-enyl alcohol 

Relevant academic research and scientific papers

Rhodium-Catalyzed Asymmetric Intramolecular Hydroamination of Allenes

The rhodium-catalyzed asymmetric intramolecular hydroamination of sulfonyl amides with terminal allenes is reported. It provides selective access to 5- and 6-membered N-heterocycles, scaffolds found in a large range of different bioactive compounds. Moreover, gram scale reactions, as well as the application of suitable product transformations to natural products and key intermediates thereof are demonstrated.

Dormant versus evolving aminopalladated intermediates: Toward a unified mechanistic scenario in PdII-catalyzed aminations

PdII-catalyzed alkene aminopalladation and allylic Ci￡H activation are two competing reaction sequences sharing the same reaction conditions. This study aimed at understanding the factors that bias one or the other path in the intramolecular oxidative cyclization of two types of N-tosyl amidoalkenes. The results obtained are in accord with the initial generation of a high-energy cyclic (5- or 6-membered) aminopalladated intermediate. However, this latter species can evolve only if the following specific conditions are met: the availability of distocyclic β-H elimination pathway, the presence of a strong terminal oxidant, or the availability of a carbopalladation pathway. Conversely, the cyclic alkylpalladium complex is only a latent species in equilibrium with the initial substrate and cannot evolve. Such a reactivity hurdle leaves the way open for alternative reactivities such as allylic Ci￡H activation of the olefinic substrate to generate a η3-allyl complex followed by its interception by the nitrogen nucleophile, [3,3]-sigmatropic rearrangement, or decomposition. This study proposes a unifying mechanistic picture that connects these competing mechanisms. Asleep or awake? Unsaturated N nucleophiles react through two competing pathways under PdII catalysis: Ci￡H allylic activation and aminopalladation. New data are in accord with the initial generation of a high-energy cyclic aminopalladated intermediate (API) that can either evolve along different pathways such as β-H elimination, oxidation, or carbopalladation, or lay dormant, the latter leading to alternative types of reactivity, such as allylic Ci￡H activation or [3,3]-sigmatropic rearrangement, gaining the upper hand (see scheme; Ts=p-toluenesulfonyl). Copyright

Striking AcOH acceleration in direct intramolecular allylie amination reactions

An experiment was conducted to demonstrate that a strong accelerating effect occurs in direct intramolecular allylic amination when the reaction is conducted in AcOH rather than in CHCl or THF. A round bottom flask under air was charged with N-tosylcarbamate 3a-j, Pd(OAc)2, bis-sulfoxide ligand LL, phenylbenzoquinone and AcOH. The reaction was allowed to stir at 45°C for 24 h. The reaction mixture was hydrolysed and extracted with AcOEt. The combined organic layers were dried over MgSO4, filtered, and concentrated in vacuo. Cyclisation of 3a was repeated in CH2Cl 2 and in AcOH by using stoichiometric amounts of Pd(OAc) without benzoquinone. Stoichiometric tests and computational DFT analysis of the palladium reoxidation step provide an overview of the structural and energetic role of acetic acid in increasing the efficacy of the entire catalytic cycle.

Silver(I)-catalyzed aminocyclization of 2,3-butadienyl and 3,4-pentadienyl carbamates: An efficient and stereoselective synthesis of 4-vinyl-2-oxazolidinones and 4-vinyltetrahydro-2H-1,3-oxazin-2-ones

Silver(I) salts in combination with an appropriate base (mostly triethylamine) catalyzed the aminocyclization of N-substituted 2,3-butadienyl carbamates 1 (benzene, 50°C) to provide 4-vinyl-2-oxazolidinones 2 in good yields. The stereoselectivity (trans-2/cis-2) ranged from 1.4 for C5-Me to >30 for C5-phenyl, isopropenyl, and t-butyl derivatives. 3,4-Pentadienyl tosylcarbamates 3, the one-carbon higher homologues of 1, underwent a similar cyclization to give 4-vinyltetrahydro-2H-1,3-oxazin-2-one 4 in synthetically useful yields and in higher trans selectivities than 1.

Regio- and stereoselective synthesis of 1,3-hydroxyl amines via palladium-catalyzed carbonate-carbamate transformation with unique stereoselectivity: Synthesis of 3-amino-4-penten-1-ols

The transformation of cyclic carbonates 1 to cyclic carbamates 4 is achieved in the presence of aryl or sulfonyl isocyanate by the catalysis of Pd(0) in high yield and with high structural flexibility. The reaction shows unique stereoselectivity: 3,4-disubstituted carbonates 2, irrespective of the composition of their stereoisomers, provide trans-5 exclusively or predominantly over cis-5. Mixtures of cis- and trans-3,5-disubstituted carbonates 3 furnish either cis-6 or trans-6 in high selectivity depending on the reaction conditions (kinetic or thermodynamic control, respectively). 1H NMR and X-ray structure analyses of 5 and 6 indicate that the stereochemical outcome is governed by an A1,2-strain between N-sulfonyl and C5-vinyl substituents.

Palladium-catalysed Regio- and Stereo-selective Synthesis of Allylic Amines

3-Vinyl-2,6-dioxacyclohexan-1-ones 1, by treatment with N-tosyl or N-arylisocyanates and a catalytic amount of Pd0, are converted into N-tosyl- and N-aryl-3-vinyl-2-aza-6-oxacyclohexan-1-ones 2 in good yields and with unique stereoselectivity.