Abstract
A series of β-amino alcohols derived from (1R, 2S)-2-amino-1,2-diphenylethanol and substituted salicylaldehydes as novel chiral tridentate ligands has been applied to an asymmetric Reformatsky reaction of aldehydes with ethyl iodoacetate in the presence of ZnMe2. This novel catalytic system produced the desired β-hydroxyl esters with moderate to good enantioselectivities (up to 81% ee) and yields for many aldehydes, including aromatic, heteroaromatic, conjugated, and aliphatic aldehydes.
GRAPHICAL ABSTRACT
Notes
a All reactions were carried out using 2 equiv ethyl iodoacetate and 2.25 equiv ZnMe2 in Et2O at RT for 1 hour with air.
b Isolated yield.
c The enantiomeric excess was determined by chiral HPLC analysis using a Chiralcel OD column.
d Determined by LC-MS.
e nd, not determined.
a All reactions were carried out using 10 mol% 1d, 2 equiv ethyl iodoacetate, and 2.25 equiv ZnMe2 in Et2O at RT for 1 h with air.
b Isolated yield.
c The enantiomeric excess was determined by chiral HPLC analysis using Chiralcel OD column and Chiralpak AS column, or by chiral GC analysis using Chiralsil Dex CB column.
d The absolute configuration of the product was assigned by comparison of HPLC retention time with values in the literature.[ Citation 18 , Citation 22 ]