Abstract Two different organocatalytic approaches for the asymmetricsynthesis of 2,3,4-trisubstituted piperidines were developed. Both approaches were based on an aza-Michael addition followed by cyclization and gave products in high enantiomeric excess. Two different organocatalytic approaches for the asymmetricsynthesis of 2,3,4-trisubstituted piperidines were developed. Both approaches were based
Synthesis of 3-Nitropyrrolidines via Dipolar Cycloaddition Reactions Using a Modular Flow Reactor
作者:Steven Ley、Marcus Baumann、Ian Baxendale
DOI:10.1055/s-0029-1219344
日期:2010.3
The generation and subsequent use of unstabilised azomethine ylides in dipolar cycloaddition reactions within a flow microreactor is demonstrated. The 3-nitropyrrolidines produced were furthermore subjected to chemoselective hydrogenation reac- tions using the H-Cube ® system. To ensure product purities in ex- cess of 90-95%, immobilised scavengers were successfully employed.
Catalyst-Free Efficient Aza-Michael Addition of Azoles to Nitroalkenes
作者:Pengfei Li、Fuk Kwong、Yinuo Wu、Jun Wang
DOI:10.1055/s-0031-1290359
日期:2012.3
An efficient aza-Michael addition of azole to nitroalkene has been developed. In this conjugate addition, no catalyst was employed and azole reacted with nitroolefin smoothly to afford new C-N bond adducts in good to excellent yields.
Highly Enantioselective One-Pot Synthesis of Spirocyclopentaneoxindoles Containing the Oxime Group by Organocatalyzed Michael Addition/ISOC/Fragmentation Sequence
A highly diastereo- and enantioselectiveorganocatalytic protocol for the synthesis of biologically important spirocyclopentaneoxindoles containing the oxime functional group from easily accessible 3-allyl-substituted oxindoles and nitroolefins has been developed by a one-pot Michaeladdition/ISOC/fragmentation sequence.
Tosyl isocyanide and ethyl chloroformate react with nitrostyrenes to afford nitro-substituted pyrroles in good yield when a catch-and-release protocol was employed as a purification strategy.