Chemo- and diastereoselective reduction of β-enamino esters: A convenient synthesis of both cis- and trans-γ-amino alcohols and β-amino esters

Article abstract of DOI:10.1021/jo00097a039

Convenient procedures for the chemo- and diastereoselective reduction of b-enamino esters 1 are described. Both cis- and trans-γ-amino alcohols 2 or b-amino esters 3 can be prepared by reduction of b-enamino esters 1, readily available starting materials, with the use of inexpensive reagents Na/i-PrOH or NaHB(OAc)₃/AcOH, respectively, and the appropriate reduction conditions. The mechanisms and diastereoselectivities for the reductions are discussed. The relative configurations and conformations of the diastereoisomeric γ-amino alcohols 2 and β-amino esters 3 obtained are established by ¹H and ¹³C NMR study and unequivocally set by their cyclic derivatives tetrahydro-1,3-oxazines 4.