TY - JOUR
T1 - Z-Enolate Geometry in the Thioamide Aldol Reaction Illuminated by the 7-Azaindoline Auxiliary
AU - Pluta, Roman
AU - Li, Zhao
AU - Kumagai, Naoya
AU - Shibasaki, Masakatsu
N1 - Funding Information:
This work was financially supported by KAKENHI (17H03025 and 18H04276 in Precisely Designed Catalysts with Customized Scaffolding) from JSPS and MEXT. We are grateful to Dr. Tomoyuki Kimura, Dr. Ryuichi Sawa, Ms. Yumiko Kubota, and Dr. Kiyoko Iijima at the Institute of Microbial Chemistry for technical support with NMR and X-ray crystallographic analysis.
Publisher Copyright:
Copyright © 2019 American Chemical Society.
PY - 2020/2/7
Y1 - 2020/2/7
N2 - Z or E enolate geometry is the primary determinant of diastereoselectivity in the aldol reaction. Although amide and thioamide enolates are anticipated to have predominantly the E geometry because of the intrinsic steric demand, spectroscopic confirmation of the geometry in solution has remained elusive, particularly in the realm of highly stereoselective catalytic asymmetric aldol reactions. Herein we demonstrate that the 7-azaindoline auxiliary enables direct observation of the exclusive formation of the Z-enolate of the thioamide en route to a highly syn-selective aldol reaction.
AB - Z or E enolate geometry is the primary determinant of diastereoselectivity in the aldol reaction. Although amide and thioamide enolates are anticipated to have predominantly the E geometry because of the intrinsic steric demand, spectroscopic confirmation of the geometry in solution has remained elusive, particularly in the realm of highly stereoselective catalytic asymmetric aldol reactions. Herein we demonstrate that the 7-azaindoline auxiliary enables direct observation of the exclusive formation of the Z-enolate of the thioamide en route to a highly syn-selective aldol reaction.
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U2 - 10.1021/acs.orglett.9b04120
DO - 10.1021/acs.orglett.9b04120
M3 - Article
C2 - 31829612
AN - SCOPUS:85076629619
SN - 1523-7060
VL - 22
SP - 791
EP - 794
JO - Organic Letters
JF - Organic Letters
IS - 3
ER -