88738-26-5Relevant academic research and scientific papers
Asymmetric nucleophilic acylation of aldehydes via 1,1-heterodisubstituted alkenes
Monenschein, Holger,Draeger, Gerald,Jung, Alexander,Kirschning, Andreas
, p. 2270 - 2280 (2007/10/03)
Aldehydes are asymmetrically acylated by a two step sequence that is initiated by a homologation step to 1,1-heterodisubstituted alkenes followed by asymmetric dihydroxylation. Thus, ketene O,S-acetals are efficiently prepared from aldehydes by a Peterson olefination with lithiated methoxy-phenylthiotrimethylsilyl methane 14 as the C-1 source. Although they are dihydroxylated with the Sharpless catalyst with moderate to good enantioselectivity (62-80% ee), the process is not efficient owing to the low chemical yields of the desired α-hydroxy methyl esters (7-37%). Use of the corresponding sulfoxide 24 or sulfon 25 led to an improved chemical yield of α-hydroxy methyl ester 19, but the stereoselectivity was diminished. In contrast, intermediate ketene O,O-acetals are prepared by a Horner-Wittig reaction with phosphine oxide 31 and are dihydroxylated both with good chemical and stereochemical yield. The concept is applicable to aromatic, aliphatic, and chiral aldehydes. For example, this short sequence allows exclusive and independent preparation of both diastereomeric heptoses 69 a and 69 b.
A New Version of the Peterson Olefination Using Bis(trimethylsilyl)methyl Derivatives and Fluoride Ion as Catalyst
Palomo, Claudio,Aizpurua, Jesus M.,Garcia, Jesus M.,Ganboa, Inaki,Cossio, F. P.,et al.
, p. 2498 - 2503 (2007/10/02)
Reaction between a variety of bis(trimethylsilyl)methyl derivatives and carbonyl compounds under fluoride ion as catalyst is described.The reaction works especially well with nonenolizable carbonyl compounds to give the expected alkenes in high yields and, in some cases, with high stereoselectivity.Application of this methodology to an intramolecular alkenation providing a tricyclic benzocarbacephem ring system is also described.
lithium and lithium. Convenient Reagents for the Facile Conversion of Aldehydes, Ketones, and 3-Alkoxy Enones into Ketene O,S-Acetal Derivatives
Hackett, Steven,Livinghouse, Tom
, p. 879 - 885 (2007/10/02)
The title organometalics have been found to react in the 1,2-sense with a variety of carbonyl compounds to provide O,S-acetal and ketene O,S-acetal derivatives in high yield.The β,γ-unsaturated O,S-acetals obtained via the reaction of methoxy(phenylthio)
METHOXYPHENYLTHIOTRIMETHYLSILYLMETHYLLITHIUM A CONVENIENT REAGENT FOR THE HOMOLOGATION OF CARBONYL COMPOUNDS
Hackett, Steven,Livinghouse, Tom
, p. 3539 - 3542 (2007/10/02)
A facile homologation procedure for the conversion of carbonyl compounds into ketene-O,S-acetals is described.These intermediers are readily converted into ketene-O-silyl,S-acetals, thioesters, and carboxamides.
