ja6b02929_si_002.cif (1.04 MB)
Dynamic Kinetic Resolution Enabled by Intramolecular Benzoin Reaction: Synthetic Applications and Mechanistic Insights
dataset
posted on 2016-06-07, 00:00 authored by Guoxiang Zhang, Shuang Yang, Xiaoyan Zhang, Qiqiao Lin, Deb. K. Das, Jian Liu, Xinqiang FangThe
highly enantio-, diastereo-, and regioselective dynamic kinetic
resolution of β-ketoesters and 1,3-diketones was achieved via
a chiral N-heterocyclic carbene catalyzed intramolecular
cross-benzoin reaction. A variety of tetralone derivatives bearing
two contiguous stereocenters and multiple functionalities were liberated
in moderate to excellent yields and with high levels of stereoselectivity
(>95% ee and >20:1 dr in most cases). In addition, the excellent
regioselectivity
control for aryl/alkyl 1,3-diketones, and the superior electronic
differentiation of 1,3-diarylketones were highlighted. Moreover, a
set of new mechanistic rationale that differs with the currently widely
accepted understanding of intramolecular benzoin reactions was established
to demonstrate the superior preference of benzoin over aldol transformation:
(1) A coexistence of competitive aldol and benzoin reactions was detected,
but a retro-aldol-irreversible benzoin process performs a vital role
in the generation of predominant benzoin products. (2) The most essential
role of an N-electron-withdrawing substituent in
triazolium catalysts was revealed to be accelerating the rate of the
benzoin transformation, rather than suppressing the aldol process
through reducing the inherent basicity of the catalyst.
History
Usage metrics
Categories
Keywords
benzoin transformationbenzoin productschiral Ntetralone derivativesMechanistic Insightsbenzoin reactionsregioselectivity controlintramolecular benzoin reactionstriazolium catalystsDynamic Kinetic Resolution Enabledheterocyclic carbeneSynthetic Applicationsaldol transformationIntramolecular Benzoin Reactionaldol process
Licence
Exports
RefWorks
BibTeX
Ref. manager
Endnote
DataCite
NLM
DC