Synthesis of Isoquinoline-Derived Diene Esters and Quinolin-2(1H)-ylidene-Substituted 1,5-Diones from Enynones and (Iso) Quinoline N-Oxides

An efficient synthetic method was developed to access isoquinoline-derived diene esters from enynones and isoquinoline-N-oxides in an atom-economic manner. The isoquinoline-substituted diene esters were obtained in moderate to excellent yields via [3 + 2]-cycloaddition and isoxazole ring opening followed by a [1,5]-sigmatropic rearrangement reaction, which resulted in one C-C and two C-O bond formations. Further, quinolin-2(1H)-ylidene-substituted 1,5-diones were achieved by reaction of enynones with quinoline-N-oxides in very good to high yields.

Automated summary

An efficient synthetic method was developed to obtain isoquinoline-derived diene esters through an atom-economic process using enynones and isoquinoline-N-oxides. The reaction involved [3 + 2]-cycloaddition, isoxazole ring opening, and [1,5]-sigmatropic rearrangement, resulting in the formation of one C-C and two C-O bonds. Additionally, quinolin-2(1H)-ylidene-substituted 1,5-diones were successfully synthesized from enynones and quinoline-N-oxides with high yields.