An efficient approach to the stereoselective synthesis of 2,6-disubstituted dihydropyrans via stannyl-Prins cyclization
作者:Magdalena Dziedzic、Bartłomiej Furman
DOI:10.1016/j.tetlet.2007.11.128
日期:2008.1
A general method has been developed for the stereoselective construction of 2,6-disubstituted dihydropyrans based on the Lewisacid-catalyzed intramolecular reactions of oxocarbenium ions with vinylstannanes. This novel methodology was applied to the enantioselective total synthesis of (−)-centrolobine.
Merging Halogen-Atom Transfer (XAT) and Cobalt Catalysis to Override E2-Selectivity in the Elimination of Alkyl Halides: A Mild Route toward <i>contra</i>-Thermodynamic Olefins
作者:Huaibo Zhao、Alastair J. McMillan、Timothée Constantin、Rory C. Mykura、Fabio Juliá、Daniele Leonori
DOI:10.1021/jacs.1c06768
日期:2021.9.15
mechanistically distinct tactic to carry E2-type eliminations on alkyl halides. This strategy exploits the interplay of α-aminoalkyl radical-mediated halogen-atom transfer (XAT) with desaturative cobalt catalysis. The methodology is high-yielding, tolerates many functionalities, and was used to access industrially relevant materials. In contrast to thermal E2eliminations where unsymmetrical substrates give regioisomeric
The Intramolecular Silyl-Modified Sakurai (ISMS) reaction. Synthetic studies towards ambruticine
作者:István E Markó、Daniel J Bayston
DOI:10.1016/s0040-4020(01)85240-6
日期:1994.1
The ISMS reaction has been used to efficiently construct the right-hand portion 3 of the antifungal antibiotic ambruticine 1.
ISMS反应已用于有效构建抗真菌抗生素氨苄青霉素1的右侧部分3。
Synthesis of allylic and homoallylic alcohols from unsaturated cyclic ethers using a mild and selective C–O reduction approach
作者:Daniel J. Mack、Boying Guo、Jon T. Njardarson
DOI:10.1039/c2cc33551d
日期:——
Unsaturated cyclic ethers can be mildly and selectively reduced with catalytic amounts of B(C(6)F(5))(3) in the presence of an alkylsilane. The allylic position is preferentially reduced with minimal or no scrambling of olefin geometry. For electronically equivalent substrates, steric factors guide the reducing agent to the least substituted site.
Prins cyclization between a homoallylic alcohol and an aldehyde, promoted by trimethylsilyl halide, afforded 4-halo-tetrahydropyrans with good to excellent yields. Thanks to the absence of the solvent and metal, the THP thus obtained have been implicated without purification in several other reactions, in a sequential way, affording in particular new indole derivatives.