The 1,3-dipolar cycloaddition of C,N-diphenylnitrone to tert-butyl vinyl ether in the presence of several chiral Ti(IV) species which incorporate different bidentate C2-symmetrical ligands has been investigated. Several complexes have shown very efficient catalytic activity. The endo/exo selectivity of the process can be dramatically reversed in relation to the uncatalysed reaction, but low enantioselectivities up to 41% ee are found. (C) 2000 Elsevier Science Ltd.
|Publication status||Published - 5 May 2000|