Abstract: Photochemical cycloaddition of 3-alkynylcycloalkenones 3a, h, c and 4 with tetramethylethylene (8) at-40 OC leads to mixtures of 1: 1 adducts that arise largely from 1, 5 closure of the biradical intermediate (eq l), providing examples of a novel [3+ 21 cycloaddition reaction. Similar reactions occur between these same ketones and l, l- dimethoxy-2-methylpropene (9) and 1, I-dimethoxyethylene (10). In several cases, these ...
[Margaretha, Paul; Rathjen, H. J.; Wolff, Steven; Agosta, William C. Journal of the Chemical Society, Chemical Communications, 1988 , # 13 p. 841 - 842]