Donor-Acceptor Cyclopropanes: Activation Enabled by a Single, Vinylogous Acceptor

Area of Science:

• Organic Chemistry
• Synthetic Chemistry
• Catalysis

Background:

• Donor-acceptor cyclopropanes are versatile synthetic intermediates.
• Strained ring systems offer unique reactivity.
• Controlling stereochemistry in cyclopropane reactions is crucial.

Purpose of the Study:

• To present a novel class of highly activated donor-acceptor cyclopropanes.
• To explore their reactivity in cycloaddition reactions.
• To investigate diastereocontrol and enantioselectivity in these transformations.

Main Methods:

• Synthesis of novel donor-acceptor cyclopropanes.
• Cycloaddition reactions with various electrophiles (aldehydes, ketones, nitriles, etc.).
• Catalysis using Brønsted and Lewis acids.
• Mechanistic and kinetic studies.

Main Results:

• Successful cycloaddition of activated cyclopropanes with diverse substrates.
• Formation of various carbo- and heterocycles.
• Demonstration of diastereocontrol via catalyst selection.
• High enantioselectivity observed in tetrahydrofuran formation using chiral cyclopropanes.

Conclusions:

• The novel cyclopropanes are highly reactive building blocks for synthesizing complex molecules.
• Catalyst control is key for achieving desired stereochemical outcomes.
• Enantiomerically pure tetrahydrofurans can be accessed efficiently.