220555-54-4Relevant academic research and scientific papers
Chiral lithium amide base-mediated rearrangement of meso-cyclohexene oxides: Asymmetric synthesis of amino- and aziridinocyclohexenols
O'Brien, Peter,Pilgram, Christopher D.
, p. 523 - 534 (2003)
Two different chiral lithium amide base routes for the synthesis of amino- and aziridino-containing cyclohexenols have been explored. The first strategy involved the diastereoselective preparation of novel meso-aziridinocyclohexene oxides and their subsequent enantioselective rearrangement using chiral bases. In this approach, the diphenyl-phosphinoyl nitrogen protecting group proved optimal and aziridinocyclohexenols of 47-68% ee were obtained. Of particular note was the smooth rearrangement of the epoxide to an allylic alcohol in the presence of an aziridine: under optimised chiral base conditions, the aziridine remained essentially unaffected. A second more straightforward strategy for introduction of an amino functionality was also investigated: (1S,4R,5S)- and (1R,4R,5S)-4,5-bis(tert-butyldimethylsilyloxy)cyclohex-2- enols, readily prepared in >95% ee using a chiral base approach, were subjected to Mitsunobu substitution using a sulfonamide and Overman rearrangement.
Stereoselective epoxidation of cyclic alkenes using m-CPBA and Oxone/trifluoroacetone - A comparison
De Sousa,O'Brien,Pilgram,Roder,Towers
, p. 391 - 392 (2007/10/03)
A comparison of the observed diastereoselectivity of epoxidation of cyclic alkenes using m-CPBA and Oxone/trifluoroacetone is reported. The results indicate that dioxirane epoxidations are sterically controlled and provide a crude model for determination
