Case 1: the single atom is the carbonyl carbon (C=O) that ends up in carbon monoxide (C≡O).
Case 2: the single atom is the nitrogen atom in the diazenyl group (N=N), which ends up as dinitrogen (N≡N).
The above are known as cheletropic eliminations because a small, stable molecule is given off in the reaction.[1]
Case 3 & 4: the single atom is the sulfur in sulfur dioxide (SO2), which joins the alkene chains to form a ring.
In organic chemistry, cheletropic reactions, also known as chelotropic reactions,[2] are a type of pericyclic reaction (a chemical reaction that involves a transition state with a cyclic array of atoms and an associated cyclic array of interacting orbitals).[1] Specifically, cheletropic reactions are a subclass of cycloadditions. The key distinguishing feature of cheletropic reactions is that on one of the reagents, both new bonds are being made to the same atom.[3]
- ^ a b Eric V. Anslyn and Dennis A. Dougherty Modern Physical Organic Chemistry University Science Books, 2006.
- ^ Chelotropic reaction IUPAC GoldBook
- ^ Ian Fleming. Frontier Orbitals and Organic Chemistry Reactions. Wiley, 1976.