Abstract
Four pyridinyl alcohols and the corresponding hemilabile pyridinyl alcoholato ruthenium carbene complexes of the Grubbs second generation-type RuCl(H2IMes)(O^N)(=CHPh), where O^N = 1-(2′-pyridinyl)-1,1-diphenyl methanolato, 1-(2′-pyridinyl)-1-(2′-chlorophenyl),1-phenyl methanolato, 1-(2′-pyridinyl)-1-(4′-chlorophenyl),1-phenyl methanolato and 1-(2′-pyridinyl)-1-(2′-methoxyphenyl),1-phenyl methanolato, are synthesized in very good yields. At high temperatures, the precatalysts showed high stability, selectivity and activity in 1-octene metathesis compared to the Grubbs first and second generation precatalysts. The 2-/4-chloro- and 4-methoxy-substituted pyridinyl alcoholato ligand-containing ruthenium precatalysts showed high performance in the 1-octene metathesis reaction in the range 80–110 °C. The hemilabile 4-methoxy-substituted pyridinyl alcoholato ligand improved the catalyst stability, activity and selectivity for 1-octene metathesis significantly at 110 °C.
Highlights
ThTehefirfsirts3t13P1PNNMMRRininvveessttiiggaattiioon of a hemilaabbiilleepprrooppeerrttyyooffSS‐O-Olilgigaanndds sininPPddcocmomplpelxeexseosfotfhtehe typtyepteratnrasn-[sP‐[dP(dO(OOCC-C‐C6H6H4-42‐2SSRR-‐kk11-‐OO))]Ph(PPh33))22((RR==iPiPr,r,tBtBuu),)w, whehreerieninonoenePPhP3hl3igliagnadndis irseprelpaclaedcebdyby a saulfsuurlfautormaotof mthe So-fO ltihgeandS‐tOo aflfiogradndcheltaotesa,fifnorsdoluctihoenla, twesa,s rienporstoeldutbioynR, auwbaesnheriempoerrteetdal.b[y10]
All of the factors showed an increase upon raising the temper1a.0ture to 90 °C, further raising the temperature to 100 °C only increased the PMPs (77%), selectivity (97%), turnover number (TON) (6928), KIn (14.11 × 10−3) and turnover frequency (TOF) (211.04 × 10−2)
All of the factors showed an increase upon raising the temperature to 90 ◦C, further raising the temperature to 100 ◦C only increased the PMPs (77%), selectivity (97%), TON (6928), KIn (14.11 × 10−3) and TOF (21.4 × 10−2)
Summary
ThTehefirfsirts3t13P1PNNMMRRininvveessttiiggaattiioon of a hemilaabbiilleepprrooppeerrttyyooffSS‐O-Olilgigaanndds sininPPddcocmomplpelxeexseosfotfhtehe typtyepteratnrasn-[sP‐[dP(dO(OOCC-C‐C6H6H4-42‐2SSRR-‐kk11-‐OO))]Ph(PPh33))22((RR==iPiPr,r,tBtBuu),)w, whehreerieninonoenePPhP3hl3igliagnadndis irseprelpaclaedcebdyby a saulfsuurlfautormaotof mthe So-fO ltihgeandS‐tOo aflfiogradndcheltaotesa,fifnorsdoluctihoenla, twesa,s rienporstoeldutbioynR, auwbaesnheriempoerrteetdal.b[y10]. TThhee ssyynntthheessiiss ooff tthhiiss ddeessiiggnn ccoonncceepptt wwaass fifirrsstt aacchhiieevveedd bbyy GGrruubbbbss eett aall.. Aclocsloelsye‐lrye-lraetleadtedprperceactaatlyalsytswt wasaaslaslososysnytnhtehseisziezdedbybyHHaafnfnerereettaal.l.[[2222]]..BBeeccaauusseeoofftthhee iinnccrreeaassee iinn tthhee ccaattaallyyttiicc lliiffeettiimmeeaassaarreessuullttooffhheemmilialabbiliiltiyty, w, weewwereereinitnetreersetsetdedininthtehdeedseigsingcnocnocnecpetpsthsohwonwinn iMn oMtioftCif. ICn. lIinnleinweiwthitthhitsh,iJso, rJodradaana[n23[2]3s]ysnytnhtehseizsiezded4 4anadndooththererruruththeenniuiumm-b‐baasseeddpprreeccaattaallyyssttssbbyy mmooddiiffyyiinngg tthhee bbiiddeennttaattee hheemmiillaabbiillee lliiggaanndd ooff HHeerrrrmmaannnn eett aall.. FFuurrtthheerrmmoorree,, iittss ooppttiimmuumm tteemmppeerraattuurree iiss 8800 ◦°CC iinn 11-‐oocctteennee mmeettaatthheessiiss. OOuurr aaiimm iiss ssyynntthheessiizziinngg aa pprreeccaattaallyysstt tthhaatt iiss aaccttiivvee,, hhiigghhllyy sseelleeccttiivvee aanndd hhaavviinngg aa lloonnggeerr ccaattaallyyttiicc lliiffeettiimmee aatt hhiigghheerr tteemmppeerraattuurreess. IInn tthhiiss ppaappeerr,, wwee iinnvveessttiiggaatteedd tthhee iinnflfluueennccee ooff aann eelleeccttrroonn‐-wwiitthhddrraawwiinngg ((CCll)) aanndd aann eelleeccttrroonn‐-ddoonnaattiinngg ((OOMMee)) ssuubbssttiittuueenntt,, oorrtthhoo oorr ppaarraa oonn oonnee ooff tthhee αα-‐pphheennyyll rriinnggss ooff 44,, oonn iittss ccaattaallyyttiicc ppeerrffoorrmmaannccee iinn 11-‐oocctteennee mmeettaatthheessiiss. IInnvveessttiiggaattiioonnssoofftthheeiirrccaattaallyyttiiccaaccttiivviittyy,, sseelleeccttiivviittyy aanndd ssttaabbiilliittyy iinn 11-‐oocctteennee mmeettaatthheessiiss wweerree mmaaddee iinn tthhee tteemmppeerraattuurree rraannggee ooff 7700––111100 ◦°CC. [[2277]] to synthesize the pyridinyl-‐alcohols 5–8 (Scheme 2). Our aim is synthesizing 1‐(2′‐pyridinyl)‐1,1‐diphenyl‐methanols having chlorine and/or methoxy substituents on one of the phenyl rings
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