Direct regio- and stereoselective synthesis of squalene 2,3;22,23-dioxide using dioxiranes

Dimethyldioxirane (DDO, 1a) and its trifluoro analog (TFDO, 1b) were employed to achieve selectively the direct transformation of squalene 2,3(S)-oxide and of squalene 2,3(R)-oxide into the corresponding 2,3(S);22(S),23-dioxide and 2,3(R);22(R),23-dioxide, respectively.