78491-88-0Relevant academic research and scientific papers
ORGANOMETALLIC CHEMISTRY UNDER HIGH PRESSURE: TRIALKYLTIN HYDRIDE ADDITION TO UNSATURATED SYSTEMS
Rahm, A.,Castaing-Degueil, M.,Pereyre, M.
, p. C29 - C32 (1982)
The influence of high pressure (10-14 kbars) on the reaction of tin hydrides with alkenes and ketones has been investigated and a marked increase of yields generally was observed.For cyclopropyl- and cyclobutyl-alkenes, adducts were formed with retention of the rings.The stereochemical outcomes of the reaction were modified.
Felkin-Anh stereoselectivity in cycloadditions of acetylketene: Evidence for a concerted, pseudopericyclic pathway
Shumway,Ham,Moer,Whittlesey,Birney
, p. 7731 - 7739 (2007/10/03)
The cycloadditions of acetylketene with α-chiral aldehydes and ketones are shown to be diastereoselective, forming a tertiary or quaternary chiral center at an acetal or ketal carbon with good stereocontrol. X-ray crystallography of a minor product (5b) shows that the major products (e.g., 4b) are those predicted by the Felkin-Anh model. Transition states are reported at the MP2/6-31G* level for the addition of ethanal to formylketene and at the B3LYP/6-31G* level for the addition of 2-phenylpropanal. The ground-state conformations of the reactants and products are used to rationalize the relative energies and geometries of the transition states without the need to invoke the Cieplak hypothesis. However, chiral substituents on the α-oxoketene show no diastereoselectivity. These experimental and computational results are only consistent with the nearly planar, pseudopericyclic transition state previously proposed.
Generation of allylic and benzylic organolithium reagents from the corresponding ester, amide, carbonate, carbamate and urea derivatives
Alonso, Emma,Guijarro, David,Martinez, Pedro,Ramon, Diego J.,Yus, Miguel
, p. 11027 - 11038 (2007/10/03)
The reaction of different allylic and benzylic non-enolisable esters or amides (1), carbonates (4), carbamates (6, 7) and ureas (8) with an excess of lithium powder and a catalytic amount of naphthalene (10%) in the presence of an electrophile [(i)PrCHO, (t)BuCHO, PhCHO, Me2CO, Et2CO, (CH2)5CO, Ph2CO, Me3SiCl] in THF at different temperatures (-78, -30 or 0°C) leads, after hydrolysis with water to the corresponding allylated or benzylated products (2).
On the Reduction of Enol Acetates and Enolates derived from α-Chiral Ketones with Lithium Tetrahydridoaluminate
Orellana, Guillermo,Perez-Ossorio, Rafael,Quiroga, Maria L.,Sanchez-Asiain, Maria P.
, p. 679 - 682 (2007/10/02)
The Z- and E-isomers of 1-acetaoxy-1,2-diphenylprop-1-ene (1) and (2), and of 3-acetoxy-4,4-dimethyl-2-phenylpent-2-ene (3) and (4), have been converted into their respective alcohols (1RR,2SS)- and (1RS,2RS)-1,2-diphenylpropan-1-ol (5) and (6), and (1RR,
The Mechanism of the Petersen Reaction. Part 2. The Effect of Reaction Conditions, and a New Model for the Addition of Carbanions to Carbonyl Derivatives in the Absence of Chelation Control
Bassindale, Allan R.,Ellis, Richard J.,Lau, Juliana C.-Y.,Taylor, Peter G.
, p. 593 - 598 (2007/10/02)
The stereochemistry of the Petersen olefination reaction between PhHSiMe3 and PhCHO has been studied under a wide variety of conditions with excellent reproducibility and extremely high yields.The effects of counterion, solvent, added salts, variation of the carbanion-forming base, and temperature have been investigated.The product stereochemistry is remarkably insensitive to the reaction conditions.The results lead to a new method of analysis of steric approach control based on the angle of approach as defined by Dunitz and Baldwin.The method involves analysis of 'primary' and 'secondary' transition-state interactions.This analysis should be generally applicable to carbanion additions in which chelation is insignificant.
Stereoselectivity in the Condensation Reactions of 1-Phenylethyl Alkyl and Phenyl Ketones with Organometallic Reagents
Alvarez-Ibarra, Carlos,Arjona, Odon,Perez-Ossorio, Rafael,Perez-Rubalcaba, Alfredo,Quiroga, Maria L.,Santesmases, Maria J.
, p. 1645 - 1648 (2007/10/02)
Stereochemical results of the condensation reactions of a series of ketones, PhCHMeCOR (R= Me, Et, Pri, But, Ph), with various organomagnesium and organolithium derivatives in ethers as solvents are reported.Results are accounted for on the basis of competition between two transition states which may adopt either Karabatsos- or Felkin-type conformations according to the nature of R, the reagent nucleophilicity, and the polarity of solvent.Polar and steric analysis of this reaction allows highly stereoselective syntheses of diastereoisomeric α-phenylalkanols to be devised.
