153184-10-2Relevant academic research and scientific papers
Atroposelectivity in the reactions of laterally lithiated tertiary amides
Clayden, Jonathan,Pink, Jennifer H.
, p. 2561 - 2564 (1997)
Lateral lithiation - electrophilic quench of 2-substituted N,N-dialkyl-1-naphthamides proceeds with high levels of diastereoselectivity in favour of one atropisomer of the product. Similar atroposelectivity may be observed in the reactions of 2-substituted benzamides, provided the products are trapped at low temperature by a subsequent in situ ortholithiation - alkylation reaction.
Atropisomeric amides as chiral, ligands: Using (-)-sparteine-directed enantioselective silylation to control the conformation of a stereogenic axis
Clayden,Johnson,Pink,Helliwell
, p. 7033 - 7040 (2000)
An enantiomerically pure (1-trimethylsilyl)ethyl group, constructed by a (-)-sparteine-directed enantioselective quench of a laterally lithiated tertiary aromatic amide, exerts powerful thermo-dynamic control over the conformation of the adjacent tertiary amide substituent. Ortholithiation and functionalization of the amide in the 6-position allows the single amide conformer to be trapped as an enantiomerically and diastereoisomerically pure amide atropisomer. Protodesilylation of the amide gives functionalized atropisomeric amides with a stereogenic axis of single absolute configuration, whose barriers to racemization have been determined by polarimetry. Enantiomerically pure amides bearing phosphine substituents are effective ligands in a Pal-catalyzed allylic substitution reaction - the first use of a nonbiaryl atropisomer as a chiral ligand - and give products with 90% ee. The rate of racemization of the phosphine-substituted amide is powerfully influenced by the presence of palladium.
Lateral lithiation in deep eutectic solvents: regioselective functionalization of substituted toluene derivatives
Arnodo, Davide,Blangetti, Marco,Ghinato, Simone,Nejrotti, Stefano,Prandi, Cristina
supporting information, p. 2391 - 2394 (2020/03/06)
The heteroatom-directed lateral lithiation of functionalized toluenes in a choline chloride-based eutectic mixture is reported. The metalations proceed within ultrafast reaction times, with a broad substrate and electrophile scope. The directing groups pr
Atroposelectivity of reactions of benzylic metalated thiobenzamides and thionaphthamides
Ach, David,Reboul, Vincent,Metzner, Patrick
, p. 3398 - 3406 (2007/10/03)
N,N-Dialkyl-2-methylbenzenecarbothioamides and naphthalenecarbothioamides were prepared by thionation of amides with Lawesson's reagent under unusual conditions. Their axial chirality was evidenced. Benzylic deprotonation of thioamides bearing N,N-diisopr
Atroposelectivity in the electrophilic substitution reactions of laterally lithiated and silylated tertiary amides
Clayden, Jonathan,Pink, Jennifer H.,Westlund, Neil,Frampton, Christopher S.
, p. 901 - 917 (2007/10/03)
Lateral lithiation-electrophilic quench of 2-alkyl-1-naphthamides and 2,6-dialkylbenzamides yields products containing an atropisomeric Ar-CO axis and a new stereogenic centre with high (generally >95:5) diastereo-selectivity. With imines as electrophiles, single diastereoisomers containing an atropisomeric axis and two new stereogenic centres are formed. 2,6-Dialkylbenzamides may be functionalised stereoselectively at both the 2- and 6-positions, leading (with imines) to symmetrical compounds bearing 1,7-related stereogenic centres. 2-Alkylbenzamides with only one ortho alkyl group are not atropisomeric at ambient temperature but are functionalised diastereoselectively by lateral lithiation-electrophilic quench at - 78°C. Stabilisation of the atropisomeric products by further lithiation and alkylation proves their diastereoselective formation. The lack of stereospecificity in the fluoride-promoted reaction of a laterally silylated 1-naphthamide with an aldehyde suggests that reported reactions of laterally silylated benzamides may also be controlled by the rotationally restricted amide group.
Controlling the regioselectivity of lithiation using kinetic isotope effects: Deuterium as a protecting group for carbon
Clayden, Jonathan,Pink, Jennifer H.,Westlund, Neil,Wilson, Francis X.
, p. 8377 - 8380 (2007/10/03)
By substituting deuterium for hydrogen at positions of high kinetic acidity in amides and carbamates, the usual regiochemical course of their reactions with alkyllithiums (ortholithiation vs. lateral lithiation vs. nucleophilic addition) can be altered or overturned by the kinetic isotope effect. The deuterium substituent functions in these reactions as a protecting group for carbon.
