Bench-Stable Stock Solutions of Silicon Grignard Reagents: Application to Iron- and Cobalt-Catalyzed Radical C(sp<sup>3</sup>
)-Si Cross-Coupling Reactions
作者:Weichao Xue、Ryosuke Shishido、Martin Oestreich
DOI:10.1002/anie.201807640
日期:2018.9.10
the preparation of silicon‐based magnesiumreagents is reported. The MgBr2 used in the lithium‐to‐magnesium transmetalation step is generated in situ from 1,2‐dibromoethane and elemental magnesium in hot THF. No precipitation of MgBr2 occurs in the heat, and transmetalation at elevated temperature leads to homogeneous stock solutions of the silicon Grignard reagents that are stable and storable in the
Highly <i>Z</i>-Selective Double Bond Transposition in Simple Alkenes and Allylarenes through a Spin-Accelerated Allyl Mechanism
作者:Daniel Kim、Guy Pillon、Daniel J. DiPrimio、Patrick L. Holland
DOI:10.1021/jacs.1c00856
日期:2021.3.3
Double-bond transposition in alkenes (isomerization) offers opportunities for the synthesis of bioactive molecules, but requires high selectivity to avoid mixtures of products. Generation of Z-alkenes, which are present in many natural products and pharmaceuticals, is particularly challenging because it is usually less thermodynamically favorable than generation of the E isomers. We report a β-dialdiminate-supported
Practical Synthesis of Allylic Silanes from Allylic Esters and Carbamates by Stereoselective Copper-Catalyzed Allylic Substitution Reactions
作者:Martin Oestreich、Gertrud Auer
DOI:10.1002/adsc.200404381
日期:2005.4
The first copper-catalyzedallylic substitution reactions of allylic acetates and carbamates employing a bis(triorganosilyl)zinc reagent are reported. This novel procedure avoids the use of stoichiometric amounts of copper salts which are usually mandatory with this chemistry. Application of this methodology to standard model substrates substantiates a high diastereoselectivity for the double bond
Silicon Grignard Reagents as Nucleophiles in Transition-Metal-Catalyzed Allylic Substitution
作者:Weichao Xue、Martin Oestreich
DOI:10.1055/s-0037-1610309
日期:2019.1
shown to promote allylic substitution reactions of allylic electrophiles with silicon Grignard reagents. The procedure was further elaborated for CuI as catalyst. The regioselectively is independent of the leaving group for primary allylic precursors, favoring α over γ. The stereochemical course of this allylictransposition was probed with a cyclic system, and anti-diastereoselectivity was obtained.
Extracyclic Stereocontrol in Addition Reaction of Crotylsilanes with 2-Substituted 2-Cyclopentenones. Stereodivergent Synthesis of (+)-Neonepetalactone and (+)-Isoneoneptalactone
作者:Li-Rui Pan、Takashi Tokoroyama
DOI:10.1246/cl.1990.1999
日期:1990.11
The additionreaction of E- and Z-crotylsilanes with 2-substituted 2-cyclopentenones showed the preference of erythro and threo products respectively. The refinement of the selectivity was investigated and the result was utilized for efficient syntheses of the title natural products.