Direct Formation of Reactive Alkynyltrichlorotins from 1-Alkynes, SnCl<sub>4</sub>, and Bu<sub>3</sub>N. A Mild Alkynylation Reagent of Aldehydes, Acetals, and Enones
A reagent system of 1-alkyne, SnCl4, and Bu3N alkynylates aldehydes, acetals, and enones under mild reaction conditions giving acetylenic alcohols, acetylenic ethers, and acetylenic ketones, respectively, in high yields. Alkynyltrichlorotins are shown to be the reactive species for these reactions.
Tandem Semipinacol-Type 1,2-Carbon Migration/Aldol Reaction toward the Construction of [5–6–7] All-Carbon Tricyclic Core of <i>Calyciphylline</i> A-Type Alkaloids
aldehyde or dimethyl acetals is reported. This reaction provides a direct and rapid way for the construction of 6-substituted spiro[4.5]decanes which extensively exist in Daphniphyllum alkaloids. By the use of this method, further construction of a [5–6–7] all-carbon tricycliccore of CalyciphyllineA-typealkaloids was also completed.
Application of Hantzsch Ester and Meyer Nitrile in Radical Alkynylation Reactions
作者:Xu Liu、Ruoyu Liu、Jie Dai、Xu Cheng、Guigen Li
DOI:10.1021/acs.orglett.8b03050
日期:2018.11.2
constructing a Csp3–Csp bond with substituted Hantzsch ester and Meyer nitrile is reported. When benziodoxole-activated alkyne was applied as the alkynyl donor, products containing Csp3–Csp bonds involving primary, secondary, and tertiary carbon centers were achieved in up to 97% yields. K2S2O8 was the optimum radical initiator in this reaction.
报道了用取代的Hantzsch酯和Meyer腈构建C sp3- C sp键的第一个例子。当使用苯并恶唑活化的炔烃作为炔基供体时,含有C sp3- C sp键的伯,仲和叔碳中心的产品收率高达97%。在该反应中,K 2 S 2 O 8是最佳的自由基引发剂。
Enhanced Diastereoselectivity in Asymmetric Crotylation Reactions Using Propargylic Dicobalt Hexacarbonyl Complexes
作者:Meng Sui、James S. Panek
DOI:10.1021/ol016016r
日期:2001.8.9
[reaction: see text] Hexacarbonyl dicobalt complexes of propargylic acetals undergo Lewis acid catalyzed crotylation reactions with enhanced levels of diastereoselectivity (dr 6 to >20:1, syn/anti) while efficiently producing stereochemically well-defined homoallylic ethers. These results are in contrast to uncomplexed propargylic acetals, which undergo the crotylation reactions with low selectivity
Homologation of acetals of .alpha.,.beta.-unsaturated carbonyl compounds with diazoesters. Synthesis of acetals of .beta.,.gamma.-unsaturated carbonyl compounds
作者:Michael P. Doyle、Mark L. Trudell、Jan W. Terpstra