2<i>H</i>-1,2-Thiaborin: A New Boron–Sulfur Heterocycle

The reaction of 2,5-dihydro-2-diisopropylamino-1,2-thiaborole (<b>5</b>) with 2 equiv of LDA followed by CH<sub>2</sub>Cl<sub>2</sub> gives 2-(diisopropylamino)-2<i>H</i>-1,2-thiaborin (<b>2c</b>), which has been spectroscopically and structurally characterized. DFT calculations indicate that formally aromatic <b>2c</b> has a limited π-delocalized bonding in its heterocyclic ring.