Stereoselective Synthesis of Highly Functionalized Nitrocyclopropanes through the Organocatalyic Michael‐Addition‐Initiated Cyclization of Bromonitromethane and β,γ‐Unsaturated α‐Ketoesters
A highly diastereo‐ and enantioselective cyclopropanation of β,γ‐unsaturated α‐ketoesters with bromonitromethane has been successfully developed through a domino Michael‐addition/intramolecular‐alkylation strategy. Acceptable yields (up to 89 %) and enantioselectivities (up to 96 % ee) have been obtained.
Diastereodivergent Catalysis Using Modularly Designed Organocatalysts: Synthesis of both<i>cis</i>- and<i>trans</i>-Fused Pyrano[2,3-<i>b</i>]pyrans
作者:Huicai Huang、Swapna Konda、John C.-G. Zhao
DOI:10.1002/anie.201510134
日期:2016.2.5
4a,8a‐tetrahydro‐2H,5H‐pyrano[2,3‐b]pyran‐7‐carboxylates have been obtained in high diastereoselectivities and enantioselectivities from the same starting materials using a tandem inverse‐electron‐demand hetero‐Diels–Alder/oxa‐Michael reaction catalyzed by modularly designed organocatalysts (MDOs). Diastereodivergence was achieved in these reactions through the direct control of the stereochemistry
4,5-DIHYDRO-1H-PYRAZOLE DERIVATIVE OR SALTS THEREOF, AND PHARMACEUTICAL COMPOSITION COMPRISING SAME
申请人:YUHAN CORPORATION
公开号:US20150291563A1
公开(公告)日:2015-10-15
The present invention provides a 4,5-dihydro-1H-pyrazole derivative or its pharmaceutically acceptable salt, a process for the preparation thereof, and a pharmaceutical composition comprising the same. The 4,5-dihydro-1H-pyrazole derivative or its pharmaceutically acceptable salt effectively increases the LXR transcriptional activity, and therefore can be usefully applied for preventing or treating a dysfunction in cholesterol metabolism, such as cholesterol gallstone, hyperlipidemia, or coronary atherosclerosis.
Unexpected Cascade Reactions of
<i>Ortho</i>
‐Hydroxyenaminones and β,γ‐Unsaturated α‐Ketoesters to Access Hydrogenated Benzoxazolepolycycles and Pyrrole−Phenol Atropisomers
作者:Xuguan Bai、Lele Wang、Ziying Zhang、Kuan Zhang、Zhanwei Bu、Yufeng Wu、Wenjing Zhang、Qilin Wang
DOI:10.1002/adsc.201900950
日期:2019.11.5
BF3 ⋅ OEt2‐catalyzed Michael addition/cyclization/dehydration sequence of ortho‐hydroxyenaminones with aromatic or aliphatic aldehyde‐derived β,γ‐unsaturated α‐ketoesters has been achieved to afford a wide range of fused hydrogenated benzoxazole polycycles in 67–95% yields in a highlydiastereoselective manner. When isatin‐derived β,γ‐unsaturated α‐ketoesters were employed as substrates, completely different reactivities
High enantioselective Michael addition of malonates to β,γ-unsaturated α-ketoesters catalyzed by bifunctional thioureas
作者:Swapna Konda、John C.-G. Zhao
DOI:10.1016/j.tetlet.2014.07.112
日期:2014.9
A highly enantioselective Michael addition of malonates to β,γ-unsaturatedα-ketoesters was achieved using cinchona alkaloid-derived thioureas as the bifunctional catalyst. The corresponding Michael addition products were obtained in excellent yields (90–99%) and ee values (up to >99% ee) using a quinidine-derived thiourea as the catalyst under neat conditions. The opposite enantiomer may be obtained