64869-25-6Relevant academic research and scientific papers
Solid phase aldol and conjugate addition reactions using Evans' oxazolidinone chiral auxiliary
Phoon, Chee Wee,Abell, Chris
, p. 2655 - 2658 (1998)
Resin-supported Evans' chiral auxiliary is used in an aldol and a conjugate addition reaction on solid phase. The experiments show that solid- phase asymmetric reactions can reproduce the high enantiomeric excesses observed in solution phase reactions and
Anti-Selective enolboration-aldolization of propanoic acid
Ramachandran, P. Veeraraghavan,Chanda, Prem B.,Otoo, Barnabas
supporting information, p. 1289 - 1291 (2014/03/21)
A systematic examination of enolboration-aldolization of propanoic acid has led to an efficient synthesis of anti-β-hydroxy-α-methyl carboxylic acids in consistently high yields and diastereoselectivities by using B-bromodicyclohexylborane as the enolizat
MNBA-mediated β-lactone formation: Mechanistic studies and application for the asymmetric total synthesis of tetrahydrolipstatin
Shiina, Isamu,Umezaki, Yuma,Kuroda, Nobutaka,Iizumi, Takashi,Nagai, Shunsuke,Katoh, Takashi
experimental part, p. 4885 - 4901 (2012/07/30)
Various β-lactones were prepared from β-hydroxycarboxylic acids by intramolecular dehydration condensation using MNBA, an effective coupling reagent, along with a nucleophilic catalyst. The transition state that provides the desired 4-membered ring model system is disclosed by density functional theory (DFT) calculations, and the structural features of the transition form are discussed. This method was successfully applied to the asymmetric total synthesis of tetrahydrolipstatin (THL), an antiobestic drug used in clinical treatment to inhibit the activity of pancreatic lipase.
Synthesis of 2-Arylethylamines by the Curtius Rearrangement
Schulze, Matthias
experimental part, p. 1461 - 1476 (2010/07/08)
2-Arylethylamine derivatives were synthesized using the Curtius reaction and with three different methods of preparing the acyl azide functional group. Carbamates derived from isocyanate were convenient protecting groups for alkylation of amines. Starting from benzaldehyde, amphetamine was prepared in three steps through an oxazolidin-2-one intermediate in 62% overall yield. Copyright Taylor & Francis Group, LLC.
Rhenium-catalyzed reaction of carbonyl compounds with ketene silyl acetals
Nishiyama, Yutaka,Kaiba, Kenta,Umeda, Rui
experimental part, p. 793 - 795 (2010/03/24)
It was found that rhenium complex is an effective catalyst for the reaction of carbonyl compounds with ketene silyl acetals. A wide range of β-silyloxy esters is obtained by the treatment of carbonyl compounds with ketene silyl acetals in the presence of
The Phenyldimethylsilyl Group as a Masked Hydroxy Group
Fleming, Ian,Henning, Rolf,Parker, David C.,Plaut, Howard E.,Sanderson, Philip E. J.
, p. 317 - 338 (2007/10/02)
A phenyldimethylsilyl group attached to carbon can be converted into hydroxy group 1->5, with retention of configuration at the migrating carbon, by any of three main methods.The first involves protodesilylation, to remove the phenyl ring from the silicon atom, followed by oxidation of the resulting functionalized silicon atom using peracid or hydrogen peroxide.The second uses mercuric acetate for the same purpose, and can be combined in one pot with the oxidative step using peracetic acid.This method has a variant in which the mercuric ion is combined with palladium(II) acetate, both in less than stoichiometric amounts.The third uses bromine, which can also be used in one pot in conjuction with peracetic acid.In this method, but not in the method based on mercuric acetate, the peracetic acid may be buffered with sodium acetate.The method using bromine as the electrophile for removing the benzene ring has a more agreeable variant in which it is administered in the form of potassium bromide, which is oxidised to bromine by the peracetic acid.The scope and limitations of each of these methods are reported with a range of examples possessing between them many of the common functional groups.Simple benzene rings, alcohols, ethers, esters, amides and nitriles are compatible with all three methods, and ketones do not undergo Baeyer-Villiger reaction under any of the conditions.Amines, however, are oxidised to amine oxides.Ketones may be brominated in the third of the three main species.The absence of acid in the third method makes it especially valuable when the phenyldimethylsilyl group has a neighbouring nucleofugal group such as hydroxy or acetoxy.Carbon-carbon double bonds are incompatible with the methods, except for terminal monosubstituted double bonds, which can survive the conditions used in the first of the three methods.
HIGHLY STEREOSELECTIVE REFORMATSKY REACTIONS OF 3-(2-BROMOPROPIONYL)-2-OXAZOLIDONE DERIVATIVES WITH VARIOUS ALDEHYDES
Ito, Yoshio,Terashima, Shiro
, p. 2821 - 2834 (2007/10/02)
The Reformatsky reactions of 3-(2-bromopropionyl)-2-oxazolidone derivatives with various aldehydes were investigated to elucidate the effects of substituents in the 2-oxazolidone moieties on their diastereoselectivities.The highest 2,3-syn-diastereoselect
Stereoselective Aldol Reactions via Enolates of α-Acylphosphonate Diesters
Longmire, Cynthia F.,Evans, Slayton A.
, p. 922 - 923 (2007/10/02)
In the reaction between the lithium enolate (2) of diethyl propionylphosphonate (1) and benzaldehyde, the syn-product (3s) is formed with high diastereoselectivity, as a result of structural rigidity caused by Li+ interactions with the phosphoryl oxygen.
Acyl Silanes. Reagents for Diastereoselective Aldol Condensations
Shinzer, Dieter
, p. 179 - 181 (2007/10/02)
The acyl silanes 4a-c have been prepared and the stereochemistry of their aldol reactions with aldehydes have been investigated; the β-hydroxy ketones obtained were transformed into β-hydroxy acids by simple oxidation with basic hydrogen peroxide.
