By irradiation 2, 4, 6-triphenyl-o-quinolesters 1 are transformed to 1, 3, 6-triphenyl-6-acyloxy- bicyclo [3.1. 0] hex-2-en-4-ones 2; the reaction is thermally reversible. Photolysis of 1 and thermal rearrangement of 2 proceed via the same ketene-intermediate 12, the existence of which is proved by formation of pentadien-carboxamides 13 in the presence of sec-amines. Structures are confirmed by spectroscopy, reactions of 2 are presented.
