l-Prolinal Dithioacetal: A Highly Effective Organocatalyst for the Direct Nitro-Michael Addition to Selected Cyclic and Aromatic Ketones
作者:Piotr Pomarański、Zbigniew Czarnocki
DOI:10.1055/s-0037-1611531
日期:2019.9
trans-β-nitrostyrenes. Also, the first asymmetric syntheses of selected 2-methyl-4-nitro-1,3-diphenylbutan-1-one derivatives by application of the obtained organocatalyst is presented. The synthesis of novel l-prolinal dithioacetal and its application as an organocatalyst for the direct Michael addition of cyclic ketones and acetophenone derivatives to trans-β-nitrostyrene and related compounds is described
Organocatalytic asymmetric Michael addition of aldehydes and ketones to nitroalkenes catalyzed by adamantoyl <scp>l</scp>-prolinamide
作者:Yongchao Wang、Dong Li、Jun Lin、Kun Wei
DOI:10.1039/c4ra11214h
日期:——
series of adamantoyl L-prolinamides have been synthesized. These compounds have been found to be highly efficient organocatalysts for the Michaeladdition of aldehydes and ketones to nitroalkenes. Under the optimized reaction conditions, the corresponding Michael adducts were obtained in good yields (up to 95%), excellent enantioselectivities (up to 99% ee) and moderate diastereoselectivities.
Michaeladditions of different aldehydes and ketones to β-nitrostyrene and 2-(β-nitrovinyl)thiophene in 1-butyl-3-methylimidazolium hexafluorophosphate ([bmim]PF6) were studied. β-Nitrostyrene was a better acceptor than 2-(β-nitrovinyl)thiophene, in terms of both reactivity and selectivity. Aldehydes proved to be better donors than ketones, which were themselves better than β-diketones. L-proline proved