Synthesis of new chiral N-alkyl Betti-base ligands via one-pot three component strategy

Abstract

Betti base derivatives were employed as chiral ligands or as chiral auxiliaries in asymmetric transformations. In particular, N-alkyl Betti base derivatives are gaining importance as excellent ligands in asymmetric reactions. However there is no appropriate method exists for regioselective N-alkylation of Betti base. Therefore there is an urgent need to develop a new protocol for the regioselective N-alkylation of chiral Betti-base. An efficient method has been developed for one-pot synthesis of chiral N-alkyl Betti-base ligands from (S)-(+)-Betti base, arylglyoxals and cyclic 1,3-C,N-binucleophiles under catalyst free conditions. The chiral N-alkyl Betti-base ligands were obtained in good yields with excellent enantioselectivities. This method is a rapid, clean and does not require catalyst and chromatographic purification. We have developed an efficient one-pot three component strategy for the synthesis of new chiral N-alkyl Betti-base ligands from (S)-(+)-Betti base, arylglyoxals and cyclic 1,3-C,N-binucleophiles in the absence of catalyst.