Abstract In reactions with sodium sulfinates of N-substituted 1, 4-benzoquinone monoimines with the quinoid ring having free positions 2 and/or 6 the fraction of products of 1, 4-addition of the sulfinate ion grows in the series ArSO 2→ MeSO 2→ CF 3 SO 2. In the case of 2, 6- dimethyl derivatives the 1, 6-addition is preferable, and the amount of products of 6, 1- addition decreases.