Switching Regioselectivity in the Allylation of Imines by N-Side Chain Tuning
摘要:
A spectacular inversion of alpha- to gamma-regioselectivity in the allylzincation of imines can be achieved by fine-tuning of the N-side chain. This approach allows easy preparation of regioisomeric amines, in racemic as well as enantiopure forms. The usefulness of the method is illustrated by the parallel asymmetric syntheses of 2,3- and 2,5-diphenylpyrrolidines.
A spectacular inversion of alpha- to gamma-regioselectivity in the allylzincation of imines can be achieved by fine-tuning of the N-side chain. This approach allows easy preparation of regioisomeric amines, in racemic as well as enantiopure forms. The usefulness of the method is illustrated by the parallel asymmetric syntheses of 2,3- and 2,5-diphenylpyrrolidines.
Pentadienyl transfer reagents based on zirconium: preparation and reactions with carbonyl compounds
‘Cp2Zr’. These complexes underwent a highly γ-regioselective and anti-stereoselective in situ addition with carbonylcompounds to afford bis(homoallylic) alcohols in good yields. The reversal of anti vs syn selectivity was simply achieved with BF3, thus expanding the synthetic potential of the reaction.