Abstract: Production of carbonyl compounds substituted in the .alpha.-position and having the formula: ##EQU1## wherein R.sup.1 is alkyl, aralkyl, phenyl, toluyl, naphthyl, alkoxy or amino; R.sup.2 is hydrogen ##EQU2## A is hydrogen, alkyl, halo or ##EQU3## R.sup.6 is hydrogen or methyl, and R.sup.11 is alkyl; wherein said compounds are formed by reacting a sulfur ylide having the formula: ##EQU4## wherein Y is the radical ##EQU5## and R.sup.9 and R.sup.10 are alkyl or phenyl, with a solution containing both an electrophilic agent A' that is converted into the radical A and a nucleophilic agent B' that is converted into the radical B. The resulting carbonyl compounds are useful as starting materials for the production of paper, textile, and leather auxiliaries, plant protection agents, alkyd resins, polyesters and polyamides.