Shifting Access from Pyrimidine‐Spirofused to Fused Benzoheterocycles by Modifying the Activated Group Position

Abstract The synthesis of pyrimidine‐spirofused indolines from 1,3,5‐triazinanes with 2‐sulfonyliminoindolines has been achieved under catalyst‐ and additive‐free conditions, in which five atoms of 1,3,5‐triazinanes were introduced to the spiro‐annulation products via a (5+1) pathway. Subsequently, this strategy was extended to 3‐aminoindoles and 3‐aminobenzothiophenes, but a different reaction pathway (3+3) was observed. In these cases, three‐atoms of 1,3,5‐triazinanes were incorporated into pyrimidine‐fused indoles/benzothiophenes. These two transformations demonstrate the potential and versatility of 1,3,5‐triazinanes to construct nitrogen‐heterocycles.