35802-48-3Relevant academic research and scientific papers
Regioselective Access to α-Vinylsilanes and α-Vinylgermanes by Cobalt-Catalyzed Migratory Hydrofunctionalization of 2-Alkynes
Chang, Sukbok,Kim, Dongwook,Park, Jung-Woo,Sahoo, Manoj Kumar
, p. 12777 - 12784 (2021/10/29)
While migratory functionalization of alkynes has been recognized as a unique way to access allylic functionalities via π-allyl metal intermediates, hydrofunctionalization of 2-alkynes to afford α-functional olefins has been unexplored. We describe herein the use of a cobalt hydride based system for regioselective migratory hydrofunctionalization of 2-alkynes to furnish α-vinylsilanes and α-vinylgermanes by a mechanistic understanding of the cobalt hydride species on alkyne π-bond migration. The key mechanism of alkyne π-bond migration by [bis(dicyclohexylphosphino)ethane]cobalt hydride is strongly supported by both experimental and computational studies, and the role of each reaction component, such as alkynes and silanes, is elucidated to rationalize the unique α-vinyl selectivity.
Stereoselective intermolecular carboazidation of chiral allylsilanes
Chabaud, Laurent,Landais, Yannick,Renaud, Philippe
, p. 4257 - 4260 (2007/10/03)
(equation presented) Easily available chiral allylsilanes were used as substrate for carboazidation reactions. For the first time, a substantial control of the stereochemistry of the azidation of acyclic nonconjugated radicals was achieved.
Free radical addition to branched allylsilanes: Stereoselective formation and elimination of β bromosilanes
Porter, Ned A.,Zhang, Guiru,Reed, Aimee D.
, p. 5773 - 5777 (2007/10/03)
Lewis acid-promoted free radical addition to 3-silyl-1-butenes occurs in good yield to give predominantly the cis-substituted alkene. The transfer reaction occurs by atom-transfer addition of the alkyl bromide precursor, an addition that occurs by Felkin-
A Regioselective and Stereospecific Synthesis of Allylsilanes from Secondary Allylic Alcohol Derivatives
Fleming, Ian,Higgins, Dick,Lawrence, Nicholas J.,Thomas, Andrew P.
, p. 3331 - 3350 (2007/10/02)
Primary and secondary allylic acetates and benzoates react with the dimethyl(phenyl)silyl-cuprate reagent to give allylsilanes, provided that the THF in which the cuprate is prepared is diluted with ether before addition of the allylic ester.The reaction is reasonably regioselective in some cases: (i) when the allylic system is more-substituted at one end than the other, as in the reactions 4->5 and 9->10; (ii) when the steric hindrance at one end is neopentyl-like, as in the reactions 15->16; and (iii) when the disubstituted double bond has the Z configuration, as in th e reactions Z-19->E-21 or, better, because the silyl group is becoming attached to the less-sterically hindered end of the allylic system, Z-20->E-22.The regioselectivity is better if a phenyl carbamate is used in place of the ester, and a three-step protocol assembling the mixed cuprate on the leaving group is used, as in the reactions 23->24 and E- or Z-29->E-21, or, best of all, because the silyl group is again becoming attached to the less-sterically hindered end of the allylic system, E- or Z-30->E-22.This sequence works well to move the silyl group onto the more substituted end of an allyl system, but only when the move is from a secondary allylic carbamate to a tertiary allylsilane, as in the reaction 38->39.Allyl(trimethyl)silanes can be made using alkyl- or aryl-cuprates on trimethylsilyl-containing allylic esters and carbamates, as in the reactions 40->41, and 43->44.The reaction of the silyl-cuprate with allylic esters and the three-step sequence with the allylic carbamates are stereochemically complementary, the former being stereospecifically anti and the latter stereospecifically syn.Homochiral allylsilanes can be ma de by these methods with high levels of stereospecificity, as shown by the synthesis of the allylsilanes 54, 58 and 59.
ORGANIC SYNTHESIS WITH REAGENTS DERIVED FROM 3R3SiMgMe AND MnCl2
Fugami, Keigo,Hibino, Jun-ichi,Nakatsukasa, Shigeki,Matsubara, Seijiro,Oshima, Koichiro,et al.
, p. 4277 - 4292 (2007/10/02)
Synthetically useful reactions mediated by reagents derived from 3 equiv. of R3SiMgMe and MnCl2 are disclosed. (1) The manganese species reacted with terminal acetylenes to give 1,2-disilylated 1-alkenes.Mono- and bis(trimethylsilyl)acetylenes gave tri- a
Regioselective Carboxylation of Silicon-Stabilized Allylic Carbanions and the Synthetic Utility of 2-Silyl-3-butenoates
Uno, Hidemitsu
, p. 2471 - 2480 (2007/10/02)
Carbanions of allylic dimethylphenylsilanes show remarkable regioselectivity toward carboxylation with carbon dioxide and methylation with methyl iodide.Methylationn of these compounds occurred preferentially at α position, although allyltrimethylsilane and allyltriphenylsilane are known to give γ selectivity toward the same electrophiles.Moreover, their aluminum "ate" complexes react with carbon dioxide regioselectively at the α position irrespective of methyl substitution pattern of the allylic moieties.The α-carboxylated allylic silanes proved to be useful synthons of 3-(methoxycarbonyl)allyl anions after esterifiaction.
NEW SYNTHESES OF VINYLSILANES AND ALLYLSILANES BY CROSS-COUPLING OF (R3Si)3MnMgMe WITH ALKENYL AND ALLYLIC COMPOUNDS
Fugami, Keigo,Oshima, Koichiro,Utimoto, Kiitiro,Nozaki, Hitosi
, p. 2161 - 2164 (2007/10/02)
The reaction of alkenyl halides, alkenyl sulfides, and enol phosphates with (R3Si)3MnMgMe provides vinylsilanes in good yields.The method is also applicable to the allylsilane synthesis from allylic sulfides and ethers.
A Synthesis of Allylsilanes in which the Silyl Group is at the More-substituted End of the Allyl Group
Fleming, Ian,Waterson, David
, p. 1809 - 1813 (2007/10/02)
The allylsilanes (8), (11), (18) - (20), and (26), have been made by a three-step sequence from αβ-unsaturated esters.The steps are conjugate addition of the phenyldimethylsilyl group, lithium aluminium hydride reduction, and selenium-mediated dehydration
SELECTIVE SYNTHESIS OF (E)-CROTYLSILANES BY REACTION OF CROTYLMAGNESIUM BROMIDE WITH HYDROSILANES IN THE PRESENCE OF DICHLORONIKKEL(II)
Hayashi, Tamio,Kabeta, Keiji,Kumada, Makoto
, p. 1499 - 1500 (2007/10/02)
Dichloronickel(II) was found to be an effective catalyst for the reaction of crotylmagnesium bromide with hydrosilanes to give (E)-crotyl-silanes selectively.
ALLYLSILANES FROM ALLYLCHLORIDES AND SILYLCUPRATES
Laycock, Bronwyn,Kitching, William,Wickham, Geoffrey
, p. 5785 - 5788 (2007/10/02)
The beneficial effects of copper (I) salts on the reactions of cyclohex-2-enyl chlorides and 3,4-epoxycyclohexene with phenyldimethylsilyllithium are reported.
