C3-Symmetric Proline-Functionalized Organocatalysts: Enantioselective Michael Addition Reactions
作者:Jarugu Narasimha Moorthy、Satyajit Saha
DOI:10.1002/ejoc.201000569
日期:2010.11
C 3 -Symmetric, tripodal catalyst 4 based on 1,3,5-triethylbenzene, which incorporates the features of a molecular receptor, is shown to catalyze Michaeladditionreactions of carbonyl compounds to β-nitrostyrenes in a high stereoselectivity (up to 99:1 dr and up to 98 % ee).
基于 1,3,5-三乙苯的 C 3 -对称三足催化剂 4 结合了分子受体的特征,显示出以高立体选择性(高达 99: 1 dr 和高达 98 % ee)。
Pyrrolidine based chiral organocatalyst for efficient asymmetric Michael addition of cyclic ketones to β-nitrostyrenes
An efficient asymmetricMichaeladdition of cyclic ketones to β-nitrostyrenes using secondary diamine as an organocatalyst derived from l-proline and (R)-α-methylbenzyl amine has been described. This pyrrolidine based catalyst 1 was found to be very effective to synthesize various γ-nitrocarbonyl compounds in good yield (up to 81%) with excellent stereoselectivity (up to >99:1 dr and >99% ee).
(up to >99:1 dr and >99% ee) without the use of any additive. (2S)-2-[(Phenylsulfinyl)methyl]pyrrolidine, derivedfrom l-proline, has been demonstrated as an efficient organocatalyst for the asymmetricMichaeladdition of cyclohexanone and cyclopentanone to β-nitrostyrenes. This pyrrolidine-based catalyst bearing a sulfoxide moiety was used to synthesize various γ-nitro carbonyl compounds in high yield
Functionalized proline with double hydrogen bonding potential: highly enantioselective Michael addition of carbonyl compounds to β-nitrostyrenes in brine
synthetic manipulation of S-proline allows access to prolinamides 5–7 as organocatalysts capable of double hydrogen bonding for enantioselectiveMichaeladdition reactions of carbonyl compounds to β-nitrostyrenes. It is shown that prolinamide catalyst 7 leads to addition products with a high diastereo- as well as enantioselectivity. The transition state structure involving the binding of electrophilic
A modular sugar-based pyrrolidine (3) was prepared and was found to be a highly enantioselective organocatalyst for the asymmetric Michael addition of ketones to nitrostyrenes. In the presence of 10 mol% of 3, a pyrrolidine unit anchored to a natural D-glucose backbone through click chemistry, the Michael additions of ketones to nitrostyrenes proceeded smoothly to generate the corresponding adducts