Abstract
The organocatalysis-based dynamic kinetic resolution (DKR) process has proved to be a powerful strategy for the construction of chiral compounds. In this feature review, we summarized recent progress on the DKR process, which was promoted by chiral bifunctional (thio)urea and squaramide catalysis via hydrogen-bonding interactions between substrates and catalysts. A wide range of asymmetric reactions involving DKR, such as asymmetric alcoholysis of azlactones, asymmetric Michael–Michael cascade reaction, and enantioselective selenocyclization, are reviewed and demonstrate the efficiency of this strategy. The (thio)urea and squaramide catalysts with dual activation would be efficient for more unmet challenges in dynamic kinetic resolution.
Highlights
T1.hIentsryondtuhcetisoins of optically pure compounds is increasingly in demand in the pharmaceutical, fine chemTichaelss,yannthdesaigs roifcouplttuicraellyinpduursetcroiemsp[o1u–n8]d.sRiseisnoclruetaisoinngolyf irnacdeemmaantedsiinstohneephoafrtmheacmeuotisctailm, fipnoertant induscthreiamliacaplps,roanadchaegsritcoulotubrteaiinndeunsatnriteisom[1–e8r]i.caRlelsyopluutiroencoofmrpacoeumnadtess[i9s,1o0n]e
Terhse stuetcrcaehsysfdurlolythidoipschleonseedpraonduecfftisccieonnttaciansecdadtheredeosutbelreeoMceinchtearesl, raenadctoionne ocfhtarlalnens-gαi-ncgyaanllo-c-αar,βb-ounnqsautautreartneadrkyesttoenreeowceitnhtetrrawnsa-4s-smuecrcceaspsftuo-ll2y-bcureteanteoda.te to construct chiral trisubstituted tetrahydrothiophenes catalyzed by amino thiourea 5 with excellent results (Scheme 6, up to 12:1 dr, >99% ee, 98% yield) [70]
The tetrahydrothiophene products contained three stereocenters, and oSncehecmhaell6e.ngAisnygmamlle-tcraicrbtohnioq-Muaicthearenla–rMyicshteareel occaesncatedrewreaascstiuocnceosfsfturalnlys-αcr-ceyaatendo-.α,β-unsaturated ketones with trans-4-mercapto-2-butenoates catalyzed by amino thiourea 5
Summary
T1.hIentsryondtuhcetisoins of optically pure compounds is increasingly in demand in the pharmaceutical, fine chemTichaelss,yannthdesaigs roifcouplttuicraellyinpduursetcroiemsp[o1u–n8]d.sRiseisnoclruetaisoinngolyf irnacdeemmaantedsiinstohneephoafrtmheacmeuotisctailm, fipnoertant induscthreiamliacaplps,roanadchaegsritcoulotubrteaiinndeunsatnriteisom[1–e8r]i.caRlelsyopluutiroencoofmrpacoeumnadtess[i9s,1o0n]e. .T1.hTioh-iMo-Michicaheal–elM–MichicahealeCl CasacsacdadeeRReeaaccttioionn Asymmetric (thio)urea catalyzed Michael–Michael cascade reactions are one of the most poAwseyrfmulmsetrtartiecg(ieths ifoo)rutrheea ecffaitcaielynzt ecdonMstriucchtaioenl–oMf icchhiaraell ccoamscpaledxe mreoalecctuiolensswairteh monueltiopfletbhoendms’ost powfoermrfautliosntraatnedgimesulftoisrtethreeoegfefinciicecnetnctoernss’tcrruecattiioonn o[6f7c,6h8i]r.aIlnco20m0p7,leWxamngolaencdulhesiswcoitwhomrkuelrtiepxlpelobroendds’ fortmheatnioovneal nthdiom-Mulitcihsateerl–eaolgdeonl irceacectniotenr,sw’ chriecahtieomnp[l6o7y,e6d8]2. Terhse stuetcrcaehsysfdurlolythidoipschleonseedpraonduecfftisccieonnttaciansecdadtheredeosutbelreeoMceinchtearesl, raenadctoionne ocfhtarlalnens-gαi-ncgyaanllo-c-αar,βb-ounnqsautautreartneadrkyesttoenreeowceitnhtetrrawnsa-4s-smuecrcceaspsftuo-ll2y-bcureteanteoda.te to construct chiral trisubstituted tetrahydrothiophenes catalyzed by amino thiourea 5 with excellent results (Scheme 6, up to 12:1 dr, >99% ee, 98% yield) [70]. The tetrahydrothiophene products contained three stereocenters, and oSncehecmhaell6e.ngAisnygmamlle-tcraicrbtohnioq-Muaicthearenla–rMyicshteareel occaesncatedrewreaascstiuocnceosfsfturalnlys-αcr-ceyaatendo-.α,β-unsaturated ketones with trans-4-mercapto-2-butenoates catalyzed by amino thiourea 5. ATshneoet ncoanndtiuocsiveeletcotitvhietiyr parlawctaicyasl adprpalmicattiiocna.llIyn 2d0e1c2r,eSaosnegd when theacnodnccoewnotrrakteirosnrewpoarsteindctrheaatsCed2-,saynmdmtehtrisicwbiass-cninocthcoonna-daulkcailvoeidt-obatsheedirthpiroaucrteiaca7l wapasplaipcpatliieodn.toIn 2012, Song aMnoldecucleos w201o6r, 2k1e, 1r3s27reported that C2-symmetric bis-cinchona-alkaloid-based thiourea 67owf 1a4 s applied to catalyze the DKR of racemic azlactones available from N-protected racemic amino acids in one pot, affordciantgalyvzaeritohue sDcKhRiroafl nraocnem-nicatauzrlaacltαon-easmaivnaoilaebslteefrrso(mScNh-epmroete1c1te,dupractoem9i5c%amyiineolda,c9id1s%ineeo)n[e8p1o].t,The steric bulkinafefsosrdoinfgthvaeritowuos cahlikraallnooind-nmatouirealtiαe-samofincoaetsatelyrss(tS7chceamnep11r,euvpetnot9t5h%eyirieslde,lf9-1a%ggeer)e[g81a]t.iTohne astnerdicexhibited concecbnoutnMrlkacoeitlnenicoeutrslneass-t2oiio0nf1ndt6-h,ie2nep1d,tew1e3np2oed7naedlnkeatnletoniednaanmntotiioioessteeielleseccotitfvicvitaiyttayilnyisntthi7tshctiarsanntrpsafroenrvsmefnoattrimtohnea.itrMiosoenrlfe.-oaMvgegorr,reetghoaevtieeoxrnp, eathrnidemeeenxxhtpaielbriat6inemoddfe14ntal and NMR-NspMcaeRtca-tlsrypozeseccttorhopesicDcopKsitRcusdotufiedrsaiecasenmadnidcsasiniznlgaglcleetoccnrreyyssstatavl alXiX-lra-abrylaeaynfraaolnmyasilNsyc-spoisnrofcitroemcntefidrmtrhaaectedtmhteihcsaeatmktihnindeosseaocfkibdiinsfudinscootinfoenbapilfout,nctional organoorcgaaafftnoaorldcyaisnttagslyvdsatorsionduoostnceohstirteaaslbtnalobinslih-snhahhtyuydrdarrlooαgg-aeenmn--ibnbooonendsedtederdse(lSsfce-halgfe-mgarge gg1a1rt,eeugspainttoees9it5ih%neryesiietolhldue,tr9io1sn%ooleuret)sio[o8lin1d].osTtrahtseeos.
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