4208-63-3Relevant academic research and scientific papers
Chemo- and Regioselective Asymmetric Friedel-Crafts Reaction of Furans and Thiophenes with α,β-Unsaturated Aldehydes through Dual Activation
Zhang, Xiao-Ru,Zhou, Su-Lan,Yuan, Yi,Du, Wei,Chen, Ying-Chun
supporting information, p. 1771 - 1774 (2017/09/30)
A highly chemo- and regioselective Friedel-Crafts alkylation reaction of furans and thiophenes has been developed, which relies on the activation from the remote conjugated Mukaiyama silyl enol ether motif. Excellent enantioslectivity is generally obtained in reactions with α,β-unsaturated aldehydes under the well-established iminium ion catalysis of a chiral secondary amine.
Remote enantioselective friedel-crafts alkylations of furans through HOMO activation
Li, Jun-Long,Yue, Cai-Zhen,Chen, Peng-Qiao,Xiao, You-Cai,Chen, Ying-Chun
supporting information, p. 5449 - 5452 (2014/06/09)
Catalytic asymmetric Friedel-Crafts alkylation is a powerful protocol for constructing a chiral C(sp2)-C(sp3) bond. Most previous examples rely on LUMO activation of the electrophiles using chiral catalysts with subsequent attack by electron-rich arenes. Presented herein is an alternative strategy in which the HOMO of the aromatic π system of 2-furfuryl ketones is raised through the formation of a formal trienamine species using a chiral primary amine. Exclusive regioselective alkylation at the 5-position occurred with alkylidenemalononitriles, and high reactivity and excellent enantioselectivity (up to 95 % ee) was obtained by this remote activation. Alternative strategy: An asymmetric and regioselective Friedel-Crafts alkylation reaction of 2-furfuryl ketones and alkylidenemalononitriles was developed and involves the in situ generation of a formal HOMO-raised trienamine species. A diversity of alkylation products were produced in moderate to excellent enantioselectivity under the catalysis of a chiral bifunctional primary amine-thiourea (1).
GENERAL RELATIONSHIPS IN THE OPENING OF THE OXIRANE RING DURING CLEAVAGE OF GLYCIDIC ACIDS
Kuroyan, R. A.,Markosyan, A. I.,Engoyan, A. P.,Vartanyan, S. A.
, p. 1709 - 1714 (2007/10/02)
By investigation of the decarboxylation of 2,3-epoxy derivatives of acids with various structures it was shown that contrary to the existing theory about the essential opening of the β (C-O) bond in the oxirane ring there are many structural types of 2,3-epoxypropionic acids, in which opening of the α (C-O) bond in the oxirane ring occurs during decarboxylation.It was also shown that these two possible reaction paths can also arise during the decarboxylation of one 2,3-epoxypropionic acid.On the basis of the obtained data a general relationship is developed for theopening of the oxirane ring during the decarboxylation of 2,3-epoxypropionic acids with any structure, and this makes it possible to predict the structure of the obtained carbonyl compound.
