SwePub
Sök i LIBRIS databas

  Utökad sökning

WFRF:(Dayaker G.)
 

Sökning: WFRF:(Dayaker G.) > (2021) > Enantioselective de...

Enantioselective deprotometalation of alkyl ferrocenecarboxylates using bimetallic bases

Dayaker, G. (författare)
Erb, W. (författare)
Hedidi, M. (författare)
visa fler...
Chevallier, F. (författare)
Blot, M. (författare)
Gros, P. C. (författare)
Hilmersson, Göran, 1966 (författare)
Gothenburg University,Göteborgs universitet,Institutionen för kemi och molekylärbiologi,Department of Chemistry and Molecular Biology
Roisnel, T. (författare)
Dorcet, V. (författare)
Bentabed-Ababsa, G. (författare)
Mongin, F. (författare)
visa färre...
 (creator_code:org_t)
2021
2021
Engelska.
Ingår i: New Journal of Chemistry. - : Royal Society of Chemistry (RSC). - 1144-0546 .- 1369-9261. ; 45:48, s. 22579-22590
  • Tidskriftsartikel (refereegranskat)
Abstract Ämnesord
Stäng  
  • The enantioselective deprotometalation of alkyl ferrocenecarboxylates (FcCO(2)R) using mixed lithium-zinc or lithium-cadmium bases is described. By using FcCO(2)Me as the substrate, chiral lithium alkyl-amidozincates prepared from exo-(alpha R)- or endo-(alpha S)-N-(alpha-phenylethyl)bornylamine (H-exo-born-R or H-endo-born-S) were tested; the best results (27% yield and 62% ee in favor of the R-P enantiomer) were obtained by using Bu-2(endo-born-S)ZnLi in tetrahydrofuran (THF) at -30 degrees C before iodolysis. Due to the low compatibility of FcCO(2)Me with alkyl-containing lithium zincates, 1 : 1 mixtures of lithium and zinc amides were tested. Chiral (H-exo-born-R or H-endo-born-S) or/and achiral (lithium 2,2,6,6-tetramethylpiperidide or lithium diisopropylamide) secondary amines gave good results, the best (81% yield and 44% ee in favor of the R-P enantiomer) being obtained by using (endo-born-S)(3)ZnLi in THF at room temperature. Among other secondary amines also prepared and/or tested, commercial (S,S)-bis(alpha-phenylethyl)amine (H-PEA-S) proved promising. After optimization of the reaction conditions, the best enantioselectivity (26% yield and 80% ee in favor of the RP enantiomer) was observed by treating a THF solution of FcCO(2)Me and Zn(PEA-S)(2) with Li-PEA-S at -80 degrees C before iodolysis. That no reaction took place with cadmium instead of zinc suggests the formation of 'ate complexes upon treatment of Cd(PEA-S)(2) by Li-PEA-S while Zn(PEA-S)(2) and Li-PEA-S would rather work in tandem (Li-PEA-S as the base and Zn(PEA-S)(2) as the in situ trap for the formed ferrocenyllithium). While FcCO(2)Me, FcCO(2)tBu and FcCO(2)iPr could be converted into their racemic 2-iodinated derivatives with a yield of 84 to 87% by employing LiTMP (2 equiv.) in the presence of ZnCl2.TMEDA (1 equiv.) as an in situ trap, their enantioselective deprotometalation rather required Li-PEA-S together with Zn(PEA-S)(2) to produce the enantio-enriched derivatives with yields of 45-82% and 71% ee.

Ämnesord

NATURVETENSKAP  -- Kemi (hsv//swe)
NATURAL SCIENCES  -- Chemical Sciences (hsv//eng)

Nyckelord

mixed lithium-cadmium
diastereoselective deprotonative metalation
mediated asymmetric-synthesis
directed ortho-metalation
planar chiral
ferrocenes
chemoselective base
catalytic synthesis
ortho-lithiation
tmp-zincate
esters
Chemistry

Publikations- och innehållstyp

ref (ämneskategori)
art (ämneskategori)

Hitta via bibliotek

Till lärosätets databas

Kungliga biblioteket hanterar dina personuppgifter i enlighet med EU:s dataskyddsförordning (2018), GDPR. Läs mer om hur det funkar här.
Så här hanterar KB dina uppgifter vid användning av denna tjänst.

 
pil uppåt Stäng

Kopiera och spara länken för att återkomma till aktuell vy