Oxidation of secondary alkanols with the system cerium ammonium nitrate—lithium bromide into ketones, α-bromo ketones, and α,α′-dibromo ketones
作者:G. I. Nikishin、L. L. Sokova、N. I. Kapustina
DOI:10.1007/s11172-010-0091-6
日期:2010.2
Oxidation of secondary alkanols with the system Ce(NH4)2(NO3)6—LiBr in aqueous acetonitrile gave ketones, α-bromo ketones, or α,α′-dibromo ketones. The selectivity of the reaction under standard conditions depends only on the molar ratio of the reagents (alkanol: CeIV: LiBr).
New methodology for the synthesis of tetrahydrofuro[3,2-b]furan-2(3H)-one derivatives, synthons of natural products with biological interest
作者:Ángel M. Montaña、Joan A. Barcia、Pedro M. Grima、Gabriele Kociok-Köhn
DOI:10.1016/j.tet.2016.09.004
日期:2016.10
the desired furofuranones with high regio- and stereoselectivity. The new synthetic method is simple, straightforward and versatile, because a wide variety of furofuranones, and with wide molecular diversity, may be prepared by adequately designing the substituents of starting materials. The resulting furofuranones may be potentially derivatized to generate chemical libraries of high molecular diversity
Synthetic methodology to prepare polysubstituted 2-aminopyrans. Synthesis of the C32–C38 subunit of immunosuppressant sanglifehrin A
作者:Ángel M. Montaña、Joan Barcia、Albert Corominas
DOI:10.1016/j.tet.2016.06.045
日期:2016.8
products with biological activity. Here a synthetic pathway to prepare this type of intermediates is presented. The methodology is based on three main steps: a) The [4+3] cycloaddition reaction of an α,α'-dihaloketone and a conveniently protected 2-aminofuran diene. b) Chemical modification of the resulting oxabicyclic cycloadduct and orthogonal protection of organic functions, and c) Reductive ozonolysis
Regio- and Stereoselective Synthesis of Acetallic Tetrahydropyrans as Building Blocks for Natural Products Preparation, via a Tandem [4+3]-Cycloaddition/Ozonolysis Process
作者:Ángel M. Montaña、Albert Corominas、Juan F. Chesa、Francisca García、Mercè Font-Bardia
DOI:10.1002/ejoc.201600590
日期:2016.9
A highly versatile synthetic pathway is presented for the preparation of polyfunctionalized acetallic tetrahydropyrans from conveniently substituted 1-methoxy-8-oxabicyclo[3.2.1]oct-6-en-3-one derivatives, as intermediates in the totalsynthesis of natural and unnatural products with structural, functional and/or biological importance. This synthetic methodology involves two key steps: a [4 + 3] cycloaddition
Cleavage of the oxygen bridge in 8-oxabicyclo[3.2.1]octanes by reductive elimination
作者:Baldur Föhlisch、Günter Kreiselmeier
DOI:10.1016/s0040-4020(01)01051-1
日期:2001.12
Several 2(4)-bromo- or chloro-8-oxabicyclo[3.2.1]oct-6-en-3-ones (2), available by [4+3] cycloaddition of monohalogeno-oxyallyl intermediates with furans, were reduced to halogenated 8-oxabicyclo[3.2.1]oct-6-en-3endo-ols (6) and saturated analogues (7). Cycloheptene-1,3trans-diols (8,11) were formed preferentially by reductive elimination.