20570-20-1Relevant academic research and scientific papers
Ambident reactivity of chloro(dialkylamino)-(diphenylphosphinoyl)methanes
Morgalyuk, Vasilii Petrovich,Strelkova, Tat'Yana Vladimirovna,Nifant'Ev, Eduard Eugenievich
, p. 93 - 100 (2012/03/07)
The chemical properties of chloro(dialkylamino)(diphenylphosphinoyl) methanes have been studied using the simplest compound of this series, chloro(dimethylamino)(diphenylphosphinoyl)methane, as an example. Chloro- (dimethylamino)(diphenylphosphinoyl)methane shows ambident reactivity when reacting with electrophiles and nucleophiles depending on coreactant nature, it behaves as either electrophilic substrate or phosphorus nucleophile. This fact can be explained by its dissociation in solutions with both C-Cl bond cleavage to give (dimethylamino)- (diphenylphosphinoyl)methyl cation and Cl- anion and C-P bond cleavage to form chloro(dimethylamino)methyl cation and diphenylphosphinite anion. The capability of chloro(dimethylamino) (diphenylphosphinoyl)methane to produce spontaneously Ph2PO-anion allows us to recommend application in organic and organophosphorus synthesis as a synthetic equivalent (synthon) of diphenylphosphinite anion.
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.
12-hetero substituted 6,11-ethano-6,11-dihydrobenzo (b) quinolizinium salts and compositions and method of use thereof
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, (2008/06/13)
1-Hetero substituted 6,11-ethano-6,11-dihydrobenzo[b]quinolizinium salts, pharmaceutical compositions containing them, and methods for the treatment or prevention of neurodegenerative disorders or neurotoxic injuries utilizing them.
