The 1,3-dipolar cycloaddition of C,N-diphenylnitrone to tert-butyl vinyl ether in the presence of several chiral B(III) complexes which incorporate different bidentate ligands has been investigated. The use of these B(III) species reverses the endo/exo diastereoselectivity in relation to the uncatalysed reaction, giving trans cycloadducts as major products. Some of the catalysts gave very fast and high yielding reactions, but the enantioselectivities were only low to moderate. (C) 2000 Elsevier Science Ltd.
|Publication status||Published - 3 Nov 2000|