66546-61-0Relevant academic research and scientific papers
Stereoselective Halo-Succinimide Facilitated α-Halogenations of Substituted α-Trialkylsilyl-β-Substituted-α,β-Unsaturated Esters
Jennings, Michael P.,Probasco, Kristina C.
, p. 8945 - 8954 (2021/07/20)
The NXS (X = Cl, Br)-mediated halogenation of a series of (E)-α-trimethylsilyl-β-alkyl(aryl)-α,β-unsaturated esters in dimethylformamide (DMF) has furnished (Z)-β-substituted-α-halogenated-α,β-unsaturated ester products in moderate to high isolated yields (58-90%) with dr values of >20:1 coupled with the inversion of olefin stereochemistry. The reaction process was hypothesized to include an initial halonium cation intermediate, followed by regioselective ring opening with DMF. Subsequentanti-E2-type concomitant elimination allowed for the stereoselective formation of the product vinylic bromo-and chloroesters.
Diastereoselective Syntheses of (E)-α-Trialkylsilyl α,β-Unsaturated Esters, α-Silane-Substituted Conjugated Silyl Ketene Acetals, and α,γ-Substituted Allylsilanes
Johnson, David A.,Mueller Hendrix, Amanda J.,Jennings, Michael P.
, p. 9914 - 9928 (2018/08/03)
The vicinal functionalization of propiolate esters via a catalytic carbocupration/silicon group migration sequence has been further investigated to include the syntheses of a wide variety of β-alkyl- and β-aryl-substituted (E)-α-silyl α,β-unsaturated esters. The ester substrates were transformed into their β, γ-unsaturated isomers by means of an LDA-mediated γ-deprotonation, extended silyl ketene acetal formation, and final α-protonation sequence. The silyl ketene acetal intermediates were also isolated, and their stereochemistries were established by NOE. The isolation of the intermediate extended silyl ketene acetals afforded further understanding of the lithium-extended dienolate structure and furnished additional support for Snieckus's proposed cyclic eight-membered transition state in the deprotonation of (Z)-α,β-unsaturated carbonyls with metallodialkylamides.
Vicinal functionalization of propiolate esters via catalytic carbocupration: Stereoselective formation of substituted vinyl silanes
Hendrix, Amanda J. Mueller,Jennings, Michael P.
supporting information; experimental part, p. 2750 - 2753 (2010/08/20)
(Figure presented) The vicinal functionalization of propiolate esters via a catalytic carbocupration-silicon group migration sequence has been investigated. We have observed that catalyst loadings as low as 5 mol % allow for good yields and excellent diastereoselectivities (>20:1) with a series of Grignard reagents for the synthesis of substituted E-vinyl silanes.
A highly stereoselective TMSOTf-mediated catalytic carbocupration of alkynoates
Mueller, Amanda J.,Jennings, Michael P.
, p. 5327 - 5329 (2008/09/17)
(Chemical Equation Presented) The TMSOTf-mediated catalytic carbocupration of ynoates has been investigated. It has been shown that catalyst loadings as low as 5 mol % readily allow for high yields and diastereosetectivities for a series of aromatic Grignard reagents. In addition, we have been successful in vicinally functionalizing 1a via initial TMSOTf-mediated catalytic carbocupration followed by a secondary electrophilic capture of the TMS allenoate intermediate.
