A Convenient and Versatile Method for the Preparation of α-Hydroxymethyl Ketone Derivatives from the Corresponding Allyl Silyl Ethers or Allyl Carboxylates
作者:Yung-Son Hon、Ying-Chieh Wong、Kuo-Jui Wu
DOI:10.1002/jccs.200800134
日期:2008.8
The ozonolysis of 1-substituted allyl silyl ethers or 1-substituted allyl carboxylates followed by treatment with bases gave the corresponding α-silyloxymethyl- or a-acyloxymethyl-ketones in good yields. It is proposed to proceed via the corresponding α-silyloxy- or α-acyloxyaldehydes intermediates followed by 1,4-group migration. The results of theoretical calculations are applicable to explain the
Highly Diastereoselective Chelation-Controlled Additions to α-Silyloxy Ketones
作者:Gretchen R. Stanton、Gamze Koz、Patrick J. Walsh
DOI:10.1021/ja201629d
日期:2011.5.25
predict that the addition of organometallic reagents to silyl-protected α-hydroxy ketones proceeds via a nonchelation pathway to give anti-diol addition products. This prediction has held true for the vast majority of additions reported in the literature, and few methods for chelation-controlled additions of organometallic reagents to silyl-protected α-hydroxy ketones have been introduced. Herein, we present
Ketones undergo soft enolization and acylation on treatment with MgBr2·OEt2, i-Pr2NEt, and various acylating agents to give 1,3-diketones. The process is particularly efficient for N-acylbenzotriazoles and O-pentafluorophenyl esters, and, in these cases, is conducted using untreated, reagent grade CH2Cl2 open to the air, thus providing an exceptionally simple approach to the synthesis of this important class of compounds.
Acyloins from Morita–Baylis–Hillman adducts: an alternative approach to the racemic total synthesis of bupropion
作者:Giovanni W. Amarante、Patrícia Rezende、Mayra Cavallaro、Fernando Coelho
DOI:10.1016/j.tetlet.2008.04.040
日期:2008.6
In this Letter, we describe an easy and straightforward strategy for the preparation of acyloins (α-hydroxyketones) from Morita–Baylis–Hillman adducts, based on a Curtius rearrangement. Different acyloins were obtained with good overall yield (>40% for three steps). To exemplify the synthetic usefulness of this strategy, total synthesis of (±)-bupropion, a dopamine, and nor-epinefrine reuptake inhibitor
Reversal of the facial diastereoselectivity in the Paternò-Büchi reaction of silyl enol ethers carrying a chiral substituent in α-position
作者:Thorsten Bach、Kai Jödicke、Birgit Wibbeling
DOI:10.1016/0040-4020(96)00610-2
日期:1996.8
diastereoselectivity in the Paternò-Büchi reaction of benzaldehyde and silyl enol ethers 1 which bear a chiral substituent R∗ in α-position has been studied. Since the regioselectivity and the simple diastereoselectivity of the photocycloaddition is very good only two diastereoisomers are obtained whose ratio reflects the facial diastereoselectivity. With the silyloxy substituted substrates 1a-1c the selectivity