Stereoselective Synthesis of Pyrido- and Pyrrolo[1,2-<i>c</i>][1,3]oxazin-1-ones via a Nucleophilic Addition–Cyclization Process of <i>N</i>,<i>O</i>-Acetal with Ynamides
作者:Pan Han、Zhuo-Ya Mao、Chang-Mei Si、Zhu Zhou、Bang-Guo Wei、Guo-Qiang Lin
DOI:10.1021/acs.joc.8b02795
日期:2019.1.18
An efficient asymmetric approach to access functionalized pyrido- and pyrrolo[1,2-c][1,3]oxazin-1-ones has been developed through a nucleophilic addition–cyclization process of N,O-acetal with ynamides. A number of substituted ynamides 8a–8o and 3-silyloxypyrrolidine or piperidine N,O-acetals 6a, 7 were amenable to this transformation, and the desired products 9a–9o, 10a–10m were obtained with excellent
Copper-Catalyzed Diastereoselective Addition of Diborylmethane to <i>N</i>-<i>tert</i>-Butanesulfinyl Aldimines: Synthesis of β-Aminoboronates
作者:Jinyoung Park、Yeosan Lee、Junghoon Kim、Seung Hwan Cho
DOI:10.1021/acs.orglett.6b00376
日期:2016.3.4
We have developed a highly chemo- and diastereoselective alkylation of N-tert-butanesulfinyl aldimines with diborylmethane. Whereas the addition of diborylmethane under metal-free conditions shows poor diastereoselectivity, the use of a copper catalyst and a bidentate phosphine ligand significantly enhances the diastereoselectivity, providing chiral β-aminoboronates in good yields. On the basis of
usually involves using expensive starting materials and harsh reaction conditions. Herein, a one-pot biocatalytic cascade process was developed for stereo- and regioselective aminohydroxylation of diverse alkenes by combining styrene monooxygenase and halohydrin dehalogenase, providing an approach to enantiopure oxazolidinones.
Stereoselective Synthesis of 1,2-Disubstituted β-Amino Alcohols by Nucleophilic Addition to <i>N</i>-<i>tert</i>-Butanesulfinyl α-Alkoxyaldimines
作者:Jared W. Evans、Jonathan A. Ellman
DOI:10.1021/jo035224p
日期:2003.12.1
N-tert-Butanesulfinyl alpha-alkoxyaldimines are readily prepared from protected (S)-lactals without epimerization at the alpha-stereocenter. Addition of ethyl and phenyl Grignard reagents, as well as the titanium enolate of methyl acetate, to the N-tert-butanesulfinyl aldimines provides 1,2-disubstituted beta-amino alcohols in good yields (73-98%) and with high diastereoselectivities. Either syn- or anti-amino alcohol products can be obtained by the appropriate choice of alcohol protecting groups and/or reaction conditions. Finally, deprotection of the addition products provides straightforward access to either syn- or anti-1,2-amino alcohols.
Towards the Total Synthesis of Pl-3: Preparation of the Eastern Fragment through a Diastereoselective SmI<sub>2</sub>-Mediated Reformatsky Reaction
作者:Rita Fürst、Christoph Lentsch、Uwe Rinner
DOI:10.1002/ejoc.201300148
日期:2013.4
The jatrophanediterpenePl-3, isolated in 2003 from Euphorbia platyphyllos, is a structurally complex natural product with highly promising biological properties that include pronounced antiproliferative activity and the inhibition of the efflux-pump activity of multidrug resistance p-glycoprotein. Herein, the synthesis of the eastern fragment of Pl-3 is outlined. The target compound is synthesized