The relative migration tendencies of various groups where R1 or R2= C, 0, or N have been studied, 2 and it has been suggested that sulfur might exhibit an enhanced migratory capacity owing to the greater participative ability of covalent sulfur than that of nitrogen or~ xygen.~ In connection with our work on the synthesis of P-lac-tams", b we have investigated the photochemical behavior of a series of diazo compounds of type 1, in which R1 and R2 ...