Highly selective 1,4- and 1,6-addition of P(O)-H compounds to p-quinones: a divergent method for the synthesis of C- and O-phosphoryl hydroquinone derivatives.

The reaction of P(O)-H compounds with p-quinones could proceed through either 1,4- or 1,6-addition pathways by employing different additives to selectively give the corresponding C- and O-phosphoryl hydroquinone derivatives in good yields. Oxidative double 1,4-addition of P(O)-H compounds to p-quinones was also achieved by tuning the solvent, affording a facile synthesis of bis-substituted hydroquinones with phosphorus functionality. Further studies on these reactions by using optically active H-phosphinates showed that all addition reactions took place stereospecifically with retention of configuration at the phosphorus center. The findings lead to the establishment of a divergent method for the synthesis of C- and O-phosphoryl hydroquinone derivatives from easily available P(O)-H compounds.