<i>Syn</i> Selective Vinylogous Mukaiyama Aldol Reaction Using <i>Z,E</i>-Vinylketene <i>N,O</i>-Acetal with Acetals
作者:Naoya Sagawa、Hiroki Moriya、Seijiro Hosokawa
DOI:10.1021/acs.orglett.6b03549
日期:2017.1.6
Stereoselective vinylogous Mukaiyama aldol reactions using the Z,E-vinylketene silyl N,O-acetal possessing a chiral auxiliary, derivedfrom (E)-3-pentenoic acid and l-valine, have been achieved. The reaction proceeded smoothly to give a syn adduct in high stereoselectivity. Since the products possess structures including δ-alkoxy-γ-methyl-α,β-unsaturated imide, this reaction would be applicable to
A selective and convenient ruthenium mediated method for the synthesis of mixed acetals and orthoesters
作者:Stanisław Krompiec、Robert Penczek、Nikodem Kuźnik、Jan Grzegorz Małecki、Marek Matlengiewicz
DOI:10.1016/j.tetlet.2006.10.138
日期:2007.1
and phenols to O-allyl compounds (allyl ethers and acroleinacetals), catalyzed by [RuCl2(PPh3)3], was examined. Intramolecular addition of an OH group, leading to the formation of cyclicacetals and orthoesters, was also investigated. As a result, a new, selective and convenient method for the synthesis of symmetrical and unsymmetrical (mixed) acetals and orthoesters was developed.
Highly selective isomerization of allyloxyalcohols either to 1-propenyl derivatives or to cyclic acetals of propanal depending on the transition metal (Ru, Rh) complex used is described together with a proposed explanation of an alternative reaction, which permits broad application of the described method.
Synthesis of <i>tert</i>-Alkyl Amino Hydroxy Carboxylic Esters via an Intermolecular Ene-Type Reaction of Oxazolones and Enol Ethers
作者:Robert A. Mosey、Jason S. Fisk、Timothy L. Friebe、Jetze J. Tepe
DOI:10.1021/ol702941f
日期:2008.3.1
tert-Alkyl amino hydroxy carboxylic acids are abundantly present within the structure of many biologically active natural products. We describe herein the synthesis of these substrates using an oxazolone-mediated ene-type reaction with enolethers followed by NaBH4 reduction of the intermediate oxazolone.