Base catalysed rearrangements involving ylide intermediates. Part 5. Thermal rearrangements of 3-dimethylaminohex-5-en-l-ynes
Abstract
Thermal rearrangements of 3-dimethylaminohex-5-en-1-ynes (5) yield biphenyls (6). The mechanism of the transformation (5)→(6) involves a sequence of (i) a [3,3] sigmatropic rearrangement, (ii) a [1,3] hydrogen shift, (iii) an electrocyclic reaction, and (iv) elimination of dimethylamine (Scheme 2).