6934-33-4Relevant academic research and scientific papers
Shuttle arylation by Rh(I) catalyzed reversible carbon–carbon bond activation of unstrained alcohols
Lutz, Marius D.R.,Gasser, Valentina C.M.,Morandi, Bill
, p. 1108 - 1119 (2021/04/19)
The advent of transfer hydrogenation and borrowing hydrogen reactions paved the way to manipulate simple alcohols in previously unthinkable manners and circumvented the need for hydrogen gas. Analogously, transfer hydrocarbylation could greatly increase the versatility of tertiary alcohols. However, this reaction remains unexplored because of the challenges associated with the catalytic cleavage of unactivated C–C bonds. Herein, we report a rhodium(I)-catalyzed shuttle arylation cleaving the C(sp2)–C(sp3) bond in unstrained triaryl alcohols via a redox-neutral β-carbon elimination mechanism. A selective transfer hydrocarbylation of substituted (hetero)aryl groups from tertiary alcohols to ketones was realized, employing benign alcohols as latent C-nucleophiles. All preliminary mechanistic experiments support a reversible β-carbon elimination/migratory insertion mechanism. In a broader context, this novel reactivity offers a new platform for the manipulation of tertiary alcohols in catalysis.
Goldberg Active Template Synthesis of a [2]Rotaxane Ligand for Asymmetric Transition-Metal Catalysis
Hoekman, Steven,Kitching, Matthew O.,Leigh, David A.,Papmeyer, Marcus,Roke, Diederik
supporting information, p. 7656 - 7659 (2015/06/30)
We report on the active template synthesis of a [2]rotaxane through a Goldberg copper-catalyzed C-N bond forming reaction. A C2-symmetric cyclohexyldiamine macrocycle directs the assembly of the rotaxane, which can subsequently serve as a ligan
Reactivity of mixed organozinc and mixed organocopper reagents: 12. Three component reaction of mixed (n-alkyl)(diaryl)zincates, chloroformates and phosphines for the synthesis of esters
?zkan, Duygu,Erdik, Ender
, p. 75 - 81 (2015/10/05)
The reaction of mixed n-butyldiphenylzincate, n-BuPh2ZnMgBr with ethyl chloroformate, ClCOOEt in the presence n-Bu3P in THF takes place with quantitative yield and phenyl group transfer to give PhCOOEt. Ethoxycarbonylation of n-BuPh2ZnMgBr is preferable to the reaction of PhMgBr forming ester and triphenylcarbinol and also to the reaction of triphenylzincate, Ph3ZnMgBr for atom economy. Group selectivity in the phosphine catalyzed C-COOR coupling of n-BuPh2ZnMgBr and n-Bu2PhZnMgBr can be controlled by changing reaction parameters. n-Bu3P catalyzed reaction of n-BuPh2ZnMgBr with ClCOOEt takes place with phenyl selectivity whereas reaction of n-Bu2PhZnMgBr with ClCOOPh results in n-butyl transfer. Catalysis by Ph3P increases n-butyl group:phenyl group transfer ratio in the ethoxycarbonylation of both zincates. Selective transfer of aryl groups in n-Bu3P catalyzed reaction of n-butyl(aryl)2ZnMgBr reagents with ClCOOEt in THF provides a new procedure for the organometallic synthesis of arenecarboxylic acid ethyl esters at room temperature.
Asymmetric hydroxylative phenol dearomatization promoted by chiral binaphthylic and biphenylic iodanes
Bosset, Cyril,Coffinier, Romain,Peixoto, Philippe A.,El Assal, Mourad,Pouysegu, Laurent,Quideau, Stephane,Miqueu, Karinne,Sotiropoulos, Jean-Marc
, p. 9860 - 9864,5 (2014/10/15)
The long-standing quest for chiral hypervalent organoiodine compounds (i.e., iodanes) as metal-free reagents for asymmetric synthesis continues. Although remarkable progress has recently been made in organoiodine-catalyzed reactions using a terminal oxidant in stoichiometric amounts, there is still a significant need for "flaskable" chiral iodane reagents. Herein, we describe the synthesis of new iodobinaphthyls and iodobiphenyls, their successful and selective DMDO-mediated oxidation into either λ3- or λ5-iodanes, and the evaluation of their capacity to promote asymmetric hydroxylative phenol dearomatization (HPD) reactions. Most notably, a C2-symmetrical biphenylic λ5-iodane promoted the HPD-induced conversion of the monoterpene thymol into the corresponding ortho-quinol-based [4+2] cyclodimer (i.e., bis(thymol)) with enantiomeric excesses of up to 94 %.
Chloride anion triggered motion in a bis-imidazolium rotaxane
Serpell, Christopher J.,Chall, Ricky,Thompson, Amber L.,Beer, Paul D.
supporting information; experimental part, p. 12052 - 12055 (2012/01/14)
We report the first bis-imidazolium-containing rotaxane, synthesised via anion templated self-assembly. Its co-conformation is controlled by a chloride anion recognition mechanism, thus demonstrating the viability of this protocol as a stimulus for shuttl
Quantitative conformational study of redox-active [2]rotaxanes, part 1: Methodology and application to a model [2]rotaxane
Altobello, Silvano,Nikitin, Kirill,Stolarczyk, Jacek K.,Lestini, Elena,Fitzmaurice, Donald
, p. 1107 - 1116 (2008/09/17)
This paper reports a novel methodology for the conformational analysis of [2]rotaxanes. It combines NMR spectroscopic (COSY, NOESY and the recently reported paramagnetic line-broadening and suppression technique) and electrochemical techniques to enable a quantitative analysis of the co-conformations of interlocked molecules and the conformations of their components. This methodology was used to study a model [2]rotaxane in solution. This [2]rotaxane consists of an axle that incorporates an electronpoor, doubly positively charged viologen that threads an electron-rich crown ether. It has been shown that the axle of the [2]rotaxane in its dicationic state adopts a folded conformation in solution and the crown ether is localised at the viologen moiety. Following a oneelectron reduction of viologen, the paramagnetic radical cation of the [2]rotaxane retains its folded conformation in solution. The data also demonstrate that in the radical cation the crown ether remains localised at the viologen, despite its reduced affinity for the singly reduced viologen. The combined quantitative NMR spectroscopic and electrochemical characterisation of the electromechanical function of the model [2]rotaxane in solution provides an important reference point for the study of switching in structurally related bistable [2]rotaxanes, which is the subject of the second part of this work.
Self-assembly, spectroscopic, and electrochemical properties of [n]rotaxanes
Ashton,Ballardini,Balzani,Belohradsky,Gandolfi,Philp,Prodi,Raymo,Reddington,Spencer,Stoddart,Venturi,Williams
, p. 4931 - 4951 (2007/10/03)
Synthetic approaches to self-assembling [n]rotaxanes incorporating Π- electron deficient bipyridinium-based dumbbell-shaped components and Π- electron rich hydroquinone-based macrocycles have been developed. In particular, the so-called slippage methodolo
New Triarylmethyl Derivatives: "Blocking Groups" for Rotaxanes and Polyrotaxanes
Gibson, Harry W.,Lee, Sang-Hun,Engen, Paul T.,Lecavalier, Pierre,Sze, Jean,et al.
, p. 3748 - 3756 (2007/10/02)
Five triarylcarbinols (8, three new compounds) were synthesized.Using carbanion chemistry the triarylmethanes (13, five new compounds) made by formic acid reduction of 8 were converted to the ω,ω,ω-triarylalkanols (15, three new compounds) and thence to the chloro (17) and iodo (18) derivatives (five new compounds).Via carbocation chemistry p-(triarylmethyl)phenols (20, two new compounds) and aniline (21, new compound) were produced.Alkylation of 20 yielded alcohol (22), benzylic bromide (23), and carboxy (25) functionalized derivatives.The alcohol, halide, phenol, aniline, and carboxylic acid functionalized triarylmethane compounds are suitable end blocking groups for rotaxanes and polyrotaxanes.
