Diastereoselective Prins-Type Reaction of Cycloalkenylcyclopropanol Silyl Ethers and α,β-Unsaturated Aldehyde Acetals
作者:Ivan L. Lysenko、Heong-Sub Oh、Jin Kun Cha
DOI:10.1021/jo071272o
日期:2007.10.1
Electrophilic addition of 1-(1-cyclohexenyl)-1-cyclopropanol trimethylsilylether to α,β-unsaturated aldehyde acetals under Lewisacidic conditions proceeds with good to excellent diastereoselectivity to afford spirocyclobutanones containing three contiguous stereocenters. A convenient entry to enantioselective syntheses is available by use of a nonracemic C2-symmetric acetal. Elaboration of the resulting
Radical cyclization–fragmentation of ω-haloalkyl cyclobutanones: a modular approach to medium-sized carbocycles
作者:Heong-Sub Oh、Jin Kun Cha
DOI:10.1016/j.tetasy.2003.07.011
日期:2003.10
Kulinkovich cyclopropanation of cycloalkene carboxylates and subsequent electrophilic addition to haloalkyl acetals, provides a convenient method for appending seven- and eight-membered rings onto cycloalkene carboxylates. An enantioselective preparation of a medium-sizedcarbocycle is possible by the use of a non-racemic, C2-symmetric acetal.
A Tandem Prins/Schmidt Reaction Approach to Marine Alkaloids: Formal and Total Syntheses of Lepadiformines A and C
作者:Angelica M. Meyer、Christopher E. Katz、Sze-Wan Li、David Vander Velde、Jeffrey Aubé
DOI:10.1021/ol100113r
日期:2010.3.19
The tricyclic core of the cylindricine or lepadiforminefamilies of alkaloid natural products was assembled via a Prins addition/intramolecular Schmidt rearrangement under Lewis acid conditions. Both single-pot and two-stage variations of this process were examined, with particular attention to the stereochemical outcome of the processes. This technology has been applied to a formal total synthesis
Formation of Five-Membered Carbocycles by Intramolecular Palladium-Catalyzed Ring Opening of <i>tert</i>-Cyclobutanols
作者:Manivannan Ethirajan、Heong-Sub Oh、Jin Kun Cha
DOI:10.1021/ol070985q
日期:2007.7.1
We report herein stereoselective formation of a functionalized five-membered carbocycle bearing a quaternary center by intramolecular palladium-catalyzed ring-opening of o-bromophenyl-tethered tert-cyclobutanols.
DAST-mediated ring-opening of cyclopropyl silyl ethers in nitriles: facile synthesis of allylic amides <i>via</i> a Ritter-type process
作者:Masayuki Kirihara、Riho Nakamura、Kana Nakakura、Kazuki Tujimoto、Mohamed S. H. Salem、Takeyuki Suzuki、Shinobu Takizawa
DOI:10.1039/d2ob00940d
日期:——
A diethylaminosulfur trifluoride (DAST)-mediated ring-opening reaction of cyclopropyl silyl ethers in nitriles produced allylic amides in moderate to good yields (up to 87%). Time course studies using ReactIR and O-isotopic labeling mechanistic studies suggested that the present reaction occurs via a Ritter-type process, leading to the formation of allylic amides.
二乙氨基三氟化硫 (DAST) 介导的环丙基甲硅烷基醚在腈中的开环反应以中等至良好的产率(高达 87%)产生烯丙基酰胺。使用 ReactIR 和 O 同位素标记机理研究的时间过程研究表明,本反应通过Ritter 型过程发生,导致烯丙基酰胺的形成。