Premium
Catalyst‐Enabled Site‐Divergent Stereoselective Michael Reactions: Overriding Intrinsic Reactivity of Enynyl Carbonyl Acceptors
Author(s) -
Uraguchi Daisuke,
Shibazaki Ryo,
Tanaka Naoya,
Yamada Kohei,
Yoshioka Ken,
Ooi Takashi
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201800057
Subject(s) - stereoselectivity , chemistry , enantioselective synthesis , reactivity (psychology) , cinchonidine , protonation , michael reaction , conjugated system , catalysis , organocatalysis , cinchona , adduct , stereochemistry , lewis acids and bases , thiourea , organic chemistry , polymer , medicine , ion , alternative medicine , pathology
A site‐divergent stereoselective Michael reaction system is developed based on the identification of two distinct catalysts. Cinchonidine‐derived thiourea catalyzes the 1,4‐addition of prochiral azlactone enolates to enynyl N ‐acyl pyrazoles in a highly diastereo‐ and enantioselective manner to give stereochemically defined alkynes, while P ‐spiro chiral triaminoiminophosphorane catalytically controls the stereoselective 1,6‐addition and the consecutive γ‐protonation of the vinylogous enolate intermediate to afford Z , E ‐configured conjugated dienes. This 1,6‐adduct serves as a valuable precursor for the synthesis of a 2‐amino‐2‐deoxy sugar.