However, it quickly became clear that something was awry, because, as noted by Frey and his collaborators very early on,[7]and explicitly recognized by Shechter,[6]the thermal decompositions of these precursors gave the same two products in a very different ratio (∼(10:90). It is now clear that the products of “carbon-carbon insertion” formed through intramolecular reactions in simple photolyses of diazo compounds owe their existence mainly to reactions of photo-excited ...