16178-83-9Relevant academic research and scientific papers
Mechanistic Study and Development of Catalytic Reactions of Sm(II)
Maity, Sandeepan,Flowers, Robert A.
, p. 3207 - 3216 (2019/02/19)
Samarium diiodide (SmI2) is one of the most widely used single-electron reductants available to organic chemists because it is effective in reducing and coupling a wide range of functional groups. Despite the broad utility and application of SmI2 in synthesis, the reagent is used in stoichiometric amounts and has a high molecular weight, resulting in a large amount of material being used for reactions requiring one or more equivalents of electrons. Although few approaches to develop catalytic reactions have been designed, they are not widely used or require specialized conditions. As a consequence, general solutions to develop catalytic reactions of Sm(II) remain elusive. Herein, we report mechanistic studies on catalytic reactions of Sm(II) employing a terminal magnesium reductant and trimethylsilyl chloride in concert with a noncoordinating proton donor source. Reactions using this approach permitted reductions with as little as 1 mol % Sm. Mechanistic studies provide strong evidence that during the reaction, SmI2 transforms into SmCl2, therefore broadening the scope of accessible reactions. Furthermore, this mechanistic approach enabled catalysis employing HMPA as a ligand, facilitating the development of catalytic Sm(II) 5-exo-trig ketyl olefin cyclization reactions. The initial work described herein will enable further development of both useful and user-friendly catalytic reactions, a long-standing, but elusive goal in Sm(II) chemistry.
Synthesis of 5-cyclodecenones via RCM and a three-pot sequence for bisannulation
Curton, Nicholas,Ornelas, Joel,Uhrinak, Abby,Rhem, Brittney,Coulter, Jess,Zhang, Joe,Joyner, P. Matthew,White, James B.
supporting information, p. 4061 - 4065 (2016/08/18)
5-Cyclodecenones were made by RCM, using the first generation Grubbs catalyst and infinite dilution in refluxing dichloromethane. A convenient one-pot procedure for making 2,6-disubstituted cyclohexanones was developed, which allowed for the synthesis of
Stereocontrol in a combined allylic azide rearrangement and intramolecular schmidt reaction
Liu, Ruzhang,Gutierrez, Osvaldo,Tantillo, Dean J.,Aube, Jeffrey
, p. 6528 - 6531 (2012/06/15)
Pre-equilibration of an interconverting set of isomeric allylic azides is coupled with an intramolecular Schmidt reaction to afford substituted lactams stereoselectively. The effect of substitution and a preliminary mechanistic study are reported. The syn
Gold- Vs. platinum-catalyzed polycyclizations by O-acyl migration. solvent-free reactions
Moreau, Xavier,Goddard, Jean-Philippe,Bernard, Matthieu,Lemiere, Gilles,Lopez-Romero, Juan Manuel,Mainetti, Emily,Marion, Nicolas,Mouries, Virginie,Thorimbert, Serge,Fensterbank, Louis,Malacria, Max
scheme or table, p. 43 - 48 (2009/04/08)
Polycyclic derivatives incorporating a cyclopropyl group have been efficiently synthesized from propargyl acetates using platinum(II), gold(I) and gold(III) catalysis. These reactions which are also viable for the preparation of medium-sized rings, proceed with a complete diastereocontrol and can also be run in neat conditions.
Mechanistic study of samarium diiodide-HMPA initiated 5-exo-trig ketyl-olefin coupling: The role of HMPA in post-electron transfer steps
Sadasivam, Dhandapani V.,Sudhadevi Antharjanam,Prasad, Edamana,Flowers II, Robert A.
, p. 7228 - 7229 (2008/12/21)
The mechanistic importance of HMPA and proton donors (methanol, 2-methyl-2-propanol, and 2,2,2-trifluoroethanol) on SmI2-initiated 5-exo-trig ketyl-olefin cyclizations has been examined using stopped-flow spectrophotometric studies. In the pres
Heterobicyclic and tricyclic nitric oxide synthase inhibitors
-
, (2015/09/24)
The current invention discloses useful bicyclic and tricyclic amidino derivative compounds, pharmaceutical compositions containing these novel compounds, and to their use as nitric oxide synthase inhibitors.
The use of 1,4-dichlorobut-2-ene as a synthetic equivalent of 4-bromo- but-1-ene
Hughes, Gregory,Lautens, Mark,Wu, Jingxiao
, p. 835 - 837 (2007/10/03)
We report a convenient two step strategy for the attachment of but-3- enyl groups to nucleophiles. Dichloride 3 is used to introduce the 3- chlorobut-2-enyl group which is converted to the desired terminal olefin with excellent regioselectivity by a Pd ca
Neighboring Group Participation in Lewis Acid-Promoted and Annulations. The Stereocontrolled Synthesis of Tricyclic Ethers
Molander, Gary A.,Cameron, Kimberly O.
, p. 5931 - 5943 (2007/10/02)
A variety of 1,4- and 1,5-keto aldehydes derived from cycloalkanes are coupled with the bis(trimethylsilyl) enol ether of methyl acetoacetate in the presence of either TMSOTf or TrSbCl6 to generate tricyclic ethers.The reactions proceed with excellent regiochemical control by a mechanism involving neighboring group participation.This mechanism involves initial formation of a bicyclic oxocarbenium ion intermediate from the keto aldehyde substrates.The geometries of selected bicyclic intermediates have been optimized using the AM1 method allowing successful prediction of the stereochemical outcomes in the cyclization in most cases.Epimerization of α-chiral keto aldehyde substrates does not appear to occur in these Lewis acid-promoted annulation reactions.
Amphiphilic Reactions by Means of Exceptionally Bulky Organoaluminum Reagents. Rational Approach for Obtaining Unusual Equatorial, Anti-Cram, and 1,4 Selectivity in Carbonyl Alkylation
Maruoka, Keiji,Itoh, Takayuki,Sakurai, Minoru,Nonoshita, Katsumasa,Yamamoto, Hisashi
, p. 3588 - 3597 (2007/10/02)
Exceptionally bulky, oxygenophilic organoaluminum reagents, methylaluminum bis(2,6-di-tert-4-alkylphenoxide) (MAD and MAT), have been successfully utilized for stereoselective activation of carbonyl moiety.Combination of MAD or MAT with carbon nucleophiles such as organolithiums or Grignard reagents generates a new amphiphilic reaction system in which the alkylation may be interpreted as the nucleophilic addition of a reactive organometallic compound to an electrophilically activated carbonyl substrate in order to account for the regio- and stereochemical consequences.In contrast to the ordinary alkylations, the amphilic alkylation disclosed herein would be categorized into the new, yet unexplored class of alkylation that exhibits high chemoselectivity to carbonyl compounds, and more significantly it allows excellent equatorial and anti-Cram selectivity in carbonyl alkylations, hitherto difficult by the existing methodologies.Further, unusual conjugate addition of organolithium reagents to α,β-unsaturated carbonyl compounds has been accomplished by using the amphiphilic reaction system.
