Stereoselective Synthesis of Functionally Rich Spirooctahydroquinoline Oxindoles via Enynamide Cycloisomerisation/[4+2]‐Addition Sequence

Abstract Creating an expedient method for synthesizing biologically significant functionally rich octahydroquinoline is a highly sought‐after yet challenging endeavour. In this report, we document an unprecedented approach to the construction of novel spirooctahydroquinoline oxindole architectures. The reaction proceeds through Pd (II) catalyzed cycloisomerisation and quinine catalyzed [4+2]‐addition sequence to afford the desired adduct in moderate to excellent yield (up to 89%) in a single diastereomer with three contiguous stereocenters including one spirocenter. An overwhelming number of libraries were generated (35 examples) reflecting the synthetic versatility and functional groups/substituents tolerance. Further, the adduct is transformed into medicinally important fluoro‐decahydroepoxyethanoquinoline spirooxindole scaffold with five contiguous stereocenters in excellent yield and selectivity (95% yield and >99:1 dr) through a three steps sequence which signifies the synthetic utility of the developed methodology.