Reactions of N-aryl(methyl, trifluoromethyl)sulfonyl-1,4-benzoquinone monoimines with sodium sulfinates

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 ArSO2 -> MeSO2 -> CF3SO2. In the case of 2,6-dimethyl derivatives the 1,6-addition is preferable, and the amount of products of 6,1-addition decreases.