Development of Phase Transfer Catalysed Cyclopropanation and Related Processes

2019-11-22T17:57:47Z (GMT) by Claudia Del Fiandra

The aim of this research is to develop new Phase-Transfer catalysed Michael and Michael tandem reactions including bifunctional catalysed Michael reactions. We have brought our own contribution to this field by establishing a few highly enantioselective procedures that used the Michael reaction of enolisable starting materials.

We describe a Michael-initiated ring closure (MIRC) reaction o f 2,3-disubstituted-1,1- cyclopropanediesters, obtained with good enantioselectivities, under operationally simple conditions and mild PTC catalysis. The study delivers a class of novel enantiopure Michael adducts which could serve as valuable building blocks and as template of high potential synthetic utility.

We have also developed a good enantioselective Michael-initiated ring closure (MIRC) reaction, starting from 3-substituted-2-(4-pyridyl)acrylonitrile compound. The study furnishes a new generation of olefins that can be used as Michael’s substrate and densely functionalized enantiopure cyclopropanes.

We describe as well a novel high enantioselective Michael addition under phase-transfer catalysis between (Z)-3-substituted-2-(4-pyridyl)acrylonitrile olefins and isocyanoacetates leading to densely functionalized cycloadducts in excellent enantiomeric excesses.

We describe in addition the tandem intermolecular [4 + 2] / intermolecular [3 + 2] cycloaddition of nitroalkenes, vinyl ethers and acrylates under homogeneous and biphasic conditions.

We finally describe the enantioselective addition of bisulfite to a,P-unsaturated ketones for the preparation of sulfonic acids in a preparative scale to afford multigram quantities of sulfonic acids in high yields and enantioselectivities.

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