Reactivity of 2-acylaminoacrylates with ketene diethyl acetal; [2 + 2] cycloadditions vs. tandem condensationsElectronic supplementary information (ESI) available: general procedures. See http://www.rsc.org/suppdata/cc/b3/b302000b/
作者:Alberto Avenoza、Jes�s H. Busto、Noelia Canal、Jes�s M. Peregrina
DOI:10.1039/b302000b
日期:——
The reactivity of 2-acylaminoacrylates with ketenediethylacetal can be modulated by means of thermal conditions to yield cyclobutanes for the preparation of protected beta-hydroxycyclobutane-alpha-amino acids, or catalytic conditions that yield cyclohexanes by tandem condensations to obtain interesting building blocks that are alternatives to Danishefsky's diene.
作者:Alberto Avenoza、Jesús H. Busto、Noelia Canal、Jesús M. Peregrina
DOI:10.1021/jo048943s
日期:2005.1.1
In this paper, we describe a thermal [2 + 2] cycloaddition involving 2-acylaminoacrylates as electron-poor acceptor alkenes, a reaction that involves a Michael-Dieckmann-type process. The reaction gives rise to a new substituted cyclobutane skeleton that can be transformed into amino acid derivatives. For example, a number of transformations were carried out to give the two pairs of stereoisomers of the 2-hydroxycyclobutane-alpha-amino acid serine analogue (C(4)Ser); compounds 22 and 23. This synthesis covers a gap in knowledge in the broad field of restricted amino acids.
Mechanistic study of the ring-size modulation in Michael–Dieckmann type reactions of 2-acylaminoacrylates with ketene diethyl acetal
作者:Alberto Avenoza、Jesús H. Busto、Noelia Canal、José I. García、Gonzalo Jiménez-Osés、Jesús M. Peregrina、Marta Pérez-Fernández
DOI:10.1039/b615220a
日期:——
An unexpected modulation of the chemoselectivity in the Michael–Dieckmann type reactions of 2-acylaminoacrylates with ketenediethylacetal is observed, depending on the nature of the acylamino group. Experimental and theoretical studies are presented to offer insights into the origin of this substituent effect in terms of a polar stepwise mechanism.