Axially Chiral Cyclic Phosphoric Acid Enabled Enantioselective Sequential Additions

Org Lett. 2019 Apr 19;21(8):2498-2503. doi: 10.1021/acs.orglett.8b04012. Epub 2019 Apr 3.

Abstract

Efficient axially chiral cyclic phosphoric acid catalyzed enantioselective sequential additions of 2-aryl-3 H-indol-3-ones, aldehydes, and diethyl 2-aminomalonate have been developed, and a new type of nitrogen-containing heterocyclic compounds, 2,3-dihydro-1 H-imidazo[1,5- a]indol-9(9a H)-one derivatives, were prepared in good yields and excellent ee values with a wide functional group tolerance, in which the reactivity and enantioselectivity of the substrates were enabled by our newly developed axially chiral cyclic phosphoric acid, ( R)-CYC-9-CPA. Furthermore, the corresponding 1 H-imidazo[1,5- a]indol-9(9a H)-ones were constructed through the easy oxidation of 2,3-dihydro-1 H-imidazo[1,5- a]indol-9(9a H)-one derivatives.

Publication types

  • Research Support, Non-U.S. Gov't