1006-06-0Relevant academic research and scientific papers
First enantioselective addition of dialkylzinc to ketones promoted by titanium(IV) derivatives
Ramon, Diego J.,Yus, Miguel
, p. 1239 - 1242 (1998)
The reaction of dimethyl or diethylzinc with ketones in the presence of a stoichiometric amount of titanium tetraisopropoxide and a catalytic amount (20 mol %) of camphorsulfonamide derivatives as chiral ligands leads to the formation of the corresponding
Epoxidation and oxygen insertion into alkane CH bonds by dioxirane do not involve detectable radical pathways
Adam, Waldemar,Curci, Ruggero,D'Accolti, Lucia,Dinoi, Anna,Fusco, Caterina,Gasparrini, Francesco,Kluge, Ralph,Paredes, Rodrigo,Schulz, Manfred,Smerz, Alexander K.,Veloza, L. Angela,Weinkoetz, Stephan,Winde, Roland
, p. 105 - 109 (1997)
The dimethyldioxirane oxidation of α-methylstyrene, trans-cyclooctene, and 1-vinyl-2,2-diphenylcyclopropane gave, under all reaction conditions employed, the corresponding epoxides in high yields. No radical products from allylie oxidation, from trans/cis isomerization, or from cyclopropylcarbinyl rearrangement (radical clock) were observed. Even for these alkenes, which are prone to radical reactions, the previously established electrophilic concerted mechanism applies, rather than the recently proposed radical mechanism. The selective hydroxylation of (-)-2-phenylbutane by dimethyldioxirane gave only (-)-2-phenylbutan-2-ol with complete retention of configuration and no loss of optical purity. Thus, a radical-chain oxidation is also discounted in the oxygen insertion into hydrocarbon C H bonds for dioxiranes.
Regioselection and enantioselection in organolanthanide-catalyzed olefin hydrosilylation. A kinetic and mechanistic study
Fu, Peng-Fei,Brard, Laurent,Li, Yanwu,Marks, Tobin J.
, p. 7157 - 7168 (1995)
This contribution describes a study of scope, regioselection, enantioselection, metal and ancillary ligand effects, and kinetics in the catalytic PhSiH3 hydrosilylation of olefins using the organolanthanide precatalysts Cp′2-LnCH(SiM
Stereoselectivity of Grignard reaction in the presence of chiral podands and crown ethers
Luk'yanenko,Lobach,Leus
, p. 273 - 277 (2004)
Reactions of ethylmagnesium bromide with benzaldehyde and acetophenone in toluene proceed stereoselectively in the presence of catalytic amounts of chiral podands and crown ethers. Under catalytic conditions theyield of the corresponding alcohols is nearl
Highly active chiral phosphoramide-Zn(II) complexes as conjugate acid-base catalysts for enantioselective organozinc addition to ketones
Hatano, Manabu,Miyamoto, Takashi,Ishihara, Kazuaki
, p. 4535 - 4538 (2007)
(Chemical Equation Presented) A highly efficient enantioselective organozinc (R2Zn) addition to ketones catalyzed by chiral phosphoramide-Zn(II) complexes (1-10 mol %) has been developed. These complexes serve as conjugate Lewis acid-Lewis base
A practical catalytic asymmetric addition of alkyl groups to ketones
Garcia, Celina,LaRochelle, Lynne K.,Walsh, Patrick J.
, p. 10970 - 10971 (2002)
Many catalysts will promote the asymmetric addition of alkylzinc reagents to aldehydes. In contrast, there are no reports of additions to ketones that are both general and highly enantioselective. We describe herein a practical catalytic asymmetric additi
Highly enantioselective addition of dialkylzinc reagents to ketones promoted by titanium tetraisopropoxide
Yus, Miguel,Ramon, Diego J.,Prieto, Oscar
, p. 2291 - 2293 (2002)
The preparation of several 1,2-bis(hydroxycamphorsulfonamido)cyclohexenes from the corresponding 1,2-cyclohexenediamine and camphorsulfonyl chloride is described. The use of these ligands to promote the enantioselective addition of dialkylzinc to ketones
Very short highly enantioselective Grignard synthesis of 2,2-disubstituted tetrahydrofurans and tetrahydropyrans
Monasterolo, Claudio,Müller-Bunz, Helge,Gilheany, Declan G.
, p. 6531 - 6538 (2019)
Phenones with elongated chains are shown to be excellent substrates for ligand-promoted asymmetric Grignard synthesis of tertiary alcohols. In turn this enables the simple, short and highly enantioselective (up to 96% ee) preparation of chiral 2,2-disubst
Catalytic asymmetric addition of alkylzinc and functionalized alkylzinc reagents to ketones
Jeon, Sang-Jin,Li, Hongmei,Garcia, Celina,LaRochelle, Lynne K.,Walsh, Patrick J.
, p. 448 - 455 (2005)
(Chemical Equation Presented) We describe our full report of the catalytic asymmetric addition of simple and functionalized dialkylzinc reagents to a broad range of saturated ketones and enones. The functionalized organozinc reagents contain esters, silyl
Harnessing the Power of the Asymmetric Grignard Synthesis of Tertiary Alcohols: Ligand Development and Improved Scope Exemplified by One-Step Gossonorol Synthesis
Gilheany, Declan G.,Kavanagh, Saranna E.
supporting information, p. 8198 - 8203 (2020/11/18)
A series of N-substituted cyclohexyldiaminophenolic ligands for the asymmetric Grignard synthesis of tertiary alcohols is reported. The 2,5-dimethylpyrrole-decorated ligand led to improved enantioselectivities and broadened the scope of the methodology. As an exemplar, we report an unprecedented highly selective one-step synthesis of gossonorol in 93% ee, also constituting the shortest formal syntheses of natural products boivinianin B and yingzhaosu C.
