Total Synthesis of Spiro[cyclohexane‐2‐indoline] Alkaloids: A Regio‐ and Diastereoselective Spirocyclization Approach

A direct spirocyclization approach for the chemical synthesis of spiro[cyclohexane‐2‐indoline] alkaloids is reported. The absolute stereochemistry was introduced by a desymmetrizing Dieckmann condensation, and the relative stereochemistry was controlled by the manipulation of the kinetic and thermodynamic pathways of the spirocyclization. By contrast to the biogenetic proposal involving the diester‐type alkaloid as the precursor, we demonstrate that chemically a common lactone‐type intermediate could bridge the chemical synthesis of this class of natural products. A direct spirocyclization approach was adopted for the concise chemical synthesis of a class of spiro[cyclohexane‐2‐indoline] alkaloids. Stereochemically complementary spirocyclic systems could be generated by manipulation of the spirocyclization pathway to favor the kinetic or thermodynamic product.