Synthesis of Deuterated γ-Lactones for Use in Stable Isotope Dilution Assays
摘要:
Two syntheses of deuterated gamma-lactones for use as internal standards in stable isotope dilution assays (SIDA) were developed. [2,2,3,3-H-2(4)]-gamma-Octa-, -gamma-deca-, and -gamma-dodecalactones with > 89% deuterium incorporation were prepared in 27, 17, and 19% overall yields, respectively, by the reduction of a doubly protected hydroxypropiolic acid with deuterium gas. [3,3,4-H-2(3)]-gamma-Octa- and -gamma-dodecalactones were prepared in 6 and 23% yields with > 92% deuterium incorporation by the free radical addition of 2-iodoacetamide to [1,1,2-H-2(3)]-1-hexene and [1,1,2-H-2(3)]-1-decene, respectively. Reaction yields were highly dependent upon the purity of the 1-alkene starting material. The deuterated gamma-lactones were evaluated as internal standards for SIDA.
Zr-promoted ‘pair’-selective and regioselective synthesis of penta-substituted benzene derivatives
摘要:
Tetra-substituted zirconacyclopentadiene derivatives, obtainable via in situ generation of zirconacyclopropenes and their cyclic carbozirconation with alkynes, can be treated with alkynyllithiums to induce 1,2-migration accompanied by aromatization and protonolysis, leading to the formation of penta-substituted benzene derivatives, in which all five substituted may be different. (C) 2003 Elsevier Ltd. All rights reserved.
SmI2-Mediated coupling reactions between iodoalkynes and ketones or aldehydes to give propargyl alcohols
作者:Munetaka Kunishima、Shinobu Tanaka、Kazuhiro Kono、Kazuhito Hioki、Shohei Tani
DOI:10.1016/0040-4039(95)00659-z
日期:1995.5
Samarium iodide (SmI2) mediates a coupling reaction between alkynyl iodides and ketones or aldehydes to give propargyl alcohols in the presence of hexamethylphosphoric triamide (HMPA) in either benzene or tetrahydrofuran (THF). An alkynylsamarium is involved as an intermediate.
Cobalt-Catalyzed gem-Cross-Dimerization of Terminal Alkynes
作者:Jia-Feng Chen、Changkun Li
DOI:10.1021/acscatal.9b05078
日期:2020.3.20
Transition-metal-catalyzed dimerization of two different terminalalkynes provides an atom-economic synthesis of valuable conjugated 1,3-enynes. Despite many catalyst systems developed, the state-of-the-art solutions are still limited to special alkynes. A practical catalyst, which could be used to cross-dimerize general aryl alkynes and aliphatic alkynes, is still highly desired. Herein we present
A Simple and Effective Co-Catalyst for Ring-Closing Enyne Metathesis Using Grubbs I type Catalysts: A Practical Alternative to “Mori’s Conditions”
作者:Guy C. Lloyd-Jones、Alan J. Robinson、Laurent Lefort、Johannes G. de Vries
DOI:10.1002/chem.201001510
日期:2010.8.16
“Catch‐and‐release”: Simple alk‐1‐enes are effective at liberating buta‐1,3‐dienes from vinyl alkylidene ruthenium complexes, as well as undergoing alkene–alkylidene exchange with enyne substrates to regenerate the alk‐1‐ene. This ability to “catch‐and‐release” ruthenium alkylidenes allows alk‐1‐enes higher than ethylene (“Mori'sconditions”) to be used as a co‐catalysts in terminal enynemetathesis with the Grubbs
Cobalt-Catalyzed (<i>E</i>)-Selective<i>anti</i>-Markovnikov Hydrosilylation of Terminal Alkynes
作者:Caizhi Wu、Wei Jie Teo、Shaozhong Ge
DOI:10.1021/acscatal.8b01410
日期:2018.7.6
regioselective and stereoselective hydrosilylation of terminalalkynes with catalysts generated from bench-stable Co(acac)2 and bisphoshpine ligands. The cobalt catalyst precursors are activated by the reaction with hydrosilanes, and air-sensitive activators, such as Grignard reagents or NaBHEt3, are not required for catalyst activation. A wide range of aromatic and aliphatic terminalalkynes underwent this