Nucleophilic Opening of Donor-Acceptor Cyclopropanes with Indoles via Hydrogen Bond Activation with 1,1,1,3,3,3-Hexafluoroisopropanol.

The treatment of donor-acceptor cyclopropanes with the a strong hydrogen bond donor, HFIP, activated the cyclopropanes (via presumed hydrogen bonding) toward homo-Michael additions with indoles as the nucleophiles. This reaction proceeded without the need for high pressure or catalysis.