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Asymmetricdeprotona0onusings‐BuLiori‐PrLiandchiraldiaminesinTHF:
Thediaminema=ers
Carbone,G.;O’Brien,P.;Hilmersson.G.
J.Am.Soc.Chem.2010,ASAP.
DOI:10.1021/ja107672h
Sparteineandsparteinesurrogate
NotcommerciallyavailableNotreadilyaccessible
NotcommerciallyavailableEasilyaccessible
Firstasymmetrictotalsynthesisof(+)‐sparteine
Smith,B.T.;Wendt,J.A.;Aube,J.Org.Le=.2002,4,2577.
Star0ngfromthechiralketone15stepsOverallyield:15.7%.
Accessto(+)‐sparteinesurrogate
FromLaburrumanagyroidesseeds(ca.£35perkgfromVilmorin,France)Simpleandhighyieldingprocess(15‐18gfrom1kg)
Dearden,M.J.;Firkin,C.R.;Hermet,J‐P.R.;O’Brien,P.J.Am.Chem.Soc.2002,124,11870.
Sparteineanditssurrogateinthereac0ons
Dearden,M.J.;Firkin,C.R.;Hermet,J‐P.R.;O’Brien,P.J.Am.Chem.Soc.2002,124,11870.
Sparteineanditssurrogateinthereac0ons
Dearden,M.J.;Firkin,C.R.;Hermet,J‐P.R.;O’Brien,P.J.Am.Chem.Soc.2002,124,11870.
Asymmetricdeprotona0on
Wu,S.;Lee,S.;Beak,P.J.Am.Chem.Soc.1996,118,715.
Willsparteinesurrogatebehavethesame?
thecomplexesoforganolithiumreagents
6LiNMRof6[Li]i‐PrLiandsparteineEt2O‐d10
thecomplexesoforganolithiumreagents6LiNMRof6[Li]i‐PrLiandsparteineinEt2O
13CNMRof6[Li]i‐PrLiandsparteine
TwodifferentLithiumenvironment
EmpiricalBauer‐Winchester‐SchleyerruleJ(6Li,13C)=(17+/‐2)/ncnc:#of6Lica0on
nc=22DifferentCHenvironment
Sparteine‐LicomplexinTHF
6LiNMRof6[Li]i‐PrLiandsparteineinTHF‐d8
Sparteine‐LicomplexinTHF
6LiNMRof6[Li]i‐PrLiandsparteineininTHF‐d8 13CNMRof6[Li]i‐PrLiandsparteineininTHF‐d8
1CHenvironment1Lica0on
1Lienvironment
thecomplexesoforganolithiumreagents6LiNMRof6[Li]i‐PrLiandsparteinesurrogateinEt2O‐d10
thecomplexesoforganolithiumreagents6LiNMRof6[Li]i‐PrLiandsparteinesurrogateinEt2O 13CNMRof6[Li]i‐PrLiandsparteinesurrogate
1Lithiumenvironment
EmpericalBauer‐Winchester‐SchleyerruleJ(6Li,13C)=(17+/‐2)/ncnc:#of6Lica0on
nc=22DifferentCHenvironment
ProposedstructureinEt2O
Sparteinesurrogate‐LicomplexinTHF
6LiNMRof6[Li]i‐PrLiandsparteineinsurrogateTHF‐d8
Sparteinesurrogate‐LicomplexinTHF
6LiNMRof6[Li]i‐PrLiandsparteineinsurrogateinTHF‐d8
13CNMRof6[Li]i‐PrLiandsparteineinsurrogateinTHF‐d8
1CHenvironment1Lica0on
1Lienvironment
ProposedstructureinTHF
Sparteinesurrogate(1.0equiv)withi‐PrLi(1.0equiv.)inTHF
Sparteine(6.0equiv.)withi‐PrLi(1.0equiv.)inTHFNocomplexwasformedwhen1.0equiv.sparteine
Testsinthereac0ons
Testsinthereac0ons
Whydoweaboutthisatall?
Aycock,D.F.Org.Process.Res.Dev.2007,11,156.
MeTHFprovidescleanorganic‐waterphasesepara0onMeTHFhasevenlowermel0ngpoint(‐136oC)thanTHF(‐108oC)MeTHFandTHFhashigherbpthanEt2O,whichmakesthema=rac0veinindustrialprocess.
Evenbe=erofMeTHF:fromarenewablesource
O
CHO
O
CH3
O
CH3
AgriculturewasteSuchascorncobs,bagasse
MeTHFproduc0onprocess
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