Design of organocatalysts for asymmetric direct syn-aldol reactions.
Two new organocatalysts 3a and 3b, derived from L-leucine and (S)-beta-amino alcohols that were prepared from L-valine, were designed and afforded the direct syn-aldol reactions of a wide scope of aldehydes with various ketones with an excellent diastereomeric ratio of up to >20/1 and enantioselectivities of up to 99% ee.
Xu
Xiao-Ying
XY
Chengdu Institute of Organic Chemistry, Chinese Academy of Sciences, Chengdu 610041, China.
Wang
Yan-Zhao
YZ
Gong
Liu-Zhu
LZ