253431-47-9Relevant academic research and scientific papers
Generation of rhodium enolates via retro-aldol reaction and its application to regioselective aldol reaction
Murakami, Kei,Ohmiya, Hirohisa,Yorimitsu, Hideki,Oshima, Koichiro
, p. 2388 - 2390 (2008/09/18)
Retro-aldol reactions of β-hydroxy ketones take place under rhodium catalysis, leading to regioselective formation of the corresponding rhodium enolates. The enolates react with aldehydes in situ to afford the corresponding aldol adducts in high yields.
Diastereomer-differentiating photochemistry of β-arylbutyrophenones: Yang cyclization versus type II elimination
Singhal, Nidhi,Koner, Apurba L.,Mal, Prasenjit,Venugopalan, Paloth,Nau, Werner M.,Moorthy, Jarugu Narasimha
, p. 14375 - 14382 (2007/10/03)
The diastereomers of ketones 2 and 3 are shown to exhibit distinct photochemical reactivities due to conformational preferences; while the anti isomers of 2 and 3 undergo efficient Yang cyclization in 75-90% yields with a remarkable diastereoselectivity (> 90%), the syn isomers predominantly undergo Norrish Type II elimination. The differences in the product profiles of the diastereomers are consistent with a mechanistic picture involving the formation of precursor diastereomeric triplet 1,4-biradicals in which the substituents at α and β-positions stabilize the cisoid (cyclization) or transoid (elimination) geometry. The fact that such a diastereomeric relationship does indeed ensue at the triplet-excited-state itself is demonstrated via the nanosecond laser-flash photolysis of model ketones 1. The diastereomeric discrimination in the product profiles observed for ketones 2 and 3 as well as in the triplet lifetimes observed for ketones 1 can both be mechanistically traced back to different conformational preferences of the ground-state diastereomeric ketones and the intermediary 1,4-biradicals. Additionally, it emerges from the present study that the syn and anti diastereomers of ketones 2 and 3 represent two extremes of a broad range of widely examined butyrophenones, which lead to varying degrees of Yang photocyclization depending on the alkyl substitution pattern.
DIASTEREOSELECTIVE ALDOL CONDENSATIONS OF TIN ENOLATES WITH ALDEHYDES
Shenvi, Sharada,Stille, J. K.
, p. 627 - 630 (2007/10/02)
The reaction of tin enolates of cyclohexanone or propiophenone with benzaldehyde at -78 deg C gives predominately the threo aldol diastereomer.
