One-pot organocatalytic domino Michael-aldol and intramolecular SN2 reactions.: Asymmetric synthesis of highly functionalized epoxycyclohexanone derivatives

The development of the organocatalytic asymmetric one-pot Michael-Darzens condensation giving highly functionalized complex epoxycyclohexanone derivatives with up to four chiral centers is presented. Depending on the reaction conditions, either the polysubstituted 7-oxa-bicyclo[4.1.0]heptan-2-one ring system or 2-chloro-cyclohex-2-enone derivatives can be formed. For the former class of compounds a high diversity in substitution pattern is demonstrated, and the optically active products are obtained in excellent diastereo- and enantioselectivities. The potential synthetic applications of the products have been demonstrated by performing a series of highly diastereoselective transformations leading to optically active products useful for the life-science industry. Furthermore, mechanistic investigations on the formation of the chiral centers in the optically active epoxycyclohexanone are presented.