Facile Synthesis of Spiro Oxindoles, Azaoxindoles, and Dihydroisoquinolone

Abstract

Formation of 1-aryl-4-oxo-cyclohexa(e)nonecarboxylates from the Diels–Alder cycloaddition of 2-trimethylsilyloxy-1,3-butadiene and Danishefsky diene with aryl- and pyridylacrylates and further conversion thereof to spirocycles is described. This provides an efficient method for spiro oxindoles, azaoxindoles, and dihydroisoquinolones.

Keywords:

• Azaoxindoles
• Diels–Alder reaction
• dihydroisoquinolone
• spirocycles

ACKNOWLEDGMENTS

The authors acknowledge Dr. Francisco Talamas and Dr. Josh Taygerly for their valuable input and the analytical department for providing the spectroscopic and physical data.

Notes

^a All are isolated yields and are not optimized.

^b Hydrogenation in the presence of Pd-C and subsequent treatment with Zn/AcOH was required for the formation of 1c.

^c An inseparable mixture of the desired product and a side product with 16 mass units higher was obtained.

^d None of the desired spirocycle was formed.

^a All are isolated yields and are not optimized.

Current name and affiliation for Christa Parmer: Christa Tatyosian, Bio-Rad Laboratories, Hercules, California, USA.