Chemo- and Diastereoselective Reduction of .beta.-Enamino Esters: A Convenient Synthesis of Both cis- and trans-.gamma.-Amino Alcohols and .beta.-Amino Esters
作者:Giuseppe Bartoli、Cristina Cimarelli、Enrico Marcantoni、Gianni Palmieri、Marino Petrini
DOI:10.1021/jo00097a039
日期:1994.9
Convenient procedures for the chemo- and diastereoselective reduction of beta-enamino esters 1 are described. Both cis- and trans-gamma-amino alcohols 2 or beta-amino esters 3 can be prepared by reduction of beta-enamino esters 1, readily available starting materials, with the use of inexpensive reagents Nali-PrOH or NaHbB(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 gamma-amino alcohols 2 and beta-amino esters 3 obtained are established by H-1 and C-13 NMR study and unequivocally set by their cyclic derivatives tetrahydro-1,3-oxazines 4.