Asymmetric Organocatalysis Enables Rapid Assembly of Portimine Precursor Chains
作者:Liubo Li、Anton El Khoury、Brennan O’Neil Clement、Carolyn Wu、Patrick G. Harran
DOI:10.1021/acs.orglett.2c00556
日期:2022.4.15
Sequential organocatalytic additions of 2-furanone and dihydroxyacetone derivatives to a crotonaldehyde lynchpin provide polyhydroxylated chains reminiscent of lactonized deoxo Kdn type sugars. Further homologation via Kulinkovich ringopening of the butyrolactone and acylation of the zinc homoenolate derived from the incipient cyclopropanol allows assembly of functionalized chain precursors to portimine
Re-visiting the diastereoselectivity of organocatalytic conjugate addition of 2-trimethylsiloxyfuran to trans-crotonaldehyde
作者:Liubo Li、Anton El Khoury、Brennan O. Clement、Patrick G. Harran
DOI:10.1016/j.tetlet.2021.153056
日期:2021.5
We describe the re-assignment of configuration previously ascribed to product diastereomers resultant from imidazolidinone-catalyzed conjugateaddition of 2-trimethylsiloxyfuran to trans-crotonaldehyde. A modified procedure that uses a diphenylprolinol catalyst was subsequently developed to selectively provide the ‘syn’ diastereomeric product in high enantiomeric excess on decagram scales.
我们描述了先前归因于由咪唑烷酮催化的将2-三甲基甲硅烷氧基呋喃加成反式巴豆醛的共轭加成物所产生的产物非对映异构体的构型的重新分配。随后开发了使用二苯基脯氨醇催化剂的改进方法,以十毫克级的对映体过量,选择性地提供“ syn ”非对映体产物。
Mukaiyama-Michael Reactions with<i>trans</i>-2,5-Diarylpyrrolidine Catalysts: Enantioselectivity Arises from Attractive Noncovalent Interactions, Not from Steric Hindrance
作者:Eeva K. Kemppainen、Gokarneswar Sahoo、Antti Piisola、Andrea Hamza、Bianka Kótai、Imre Pápai、Petri M. Pihko
DOI:10.1002/chem.201304240
日期:2014.5.12
the predicted and observed stereoselectivities. The analysis of intermolecular forces reveals that the enantioselectivity is mostly due to stabilizing noncovalentinteractions between the reacting partners, not due to sterichindrance. The role of attractivenoncovalentinteractions in enantioselective catalysis may be underappreciated.