Michael Holtz-MulhollandLiterature MeetingSeptember 28th 2011

Im from Montreal*

The ReactionMechanismCatalyst SystemsReaction AspectsApplications*

Exchange of terminiMetal catalyzed*Montreaux, A.; Blanchard, M. J. Chem. Soc. Chem. Comm., 1974, 786.

1981: Schrock demonstrated alkylidyne is an active species1982: Schrock successfully isolated a metallacyclobutadiene from metathesis conditions*Wengrovius, J.H.; Sancho, J.; Schrock, R.R. J. Am. Chem. Soc. 1981, 103, 3932.Pedersen, S.F.; Schrock, R.R.; Churchill, M.R.; Wasserman, H.J. J. Am. Chem. Soc., 1982, 104, 6808.

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Mo(CO)6 and phenolEarliest examplesRelatively stableLow functional group toleranceRequires high temperatureIll-defined active species*

Grela: optimization of the phenol sourceOptimal Pka between 8 and 9*Grela, K.; Ignatowska, J. Org. Lett., 2002, 4, 3747.Sashuk, V.; Ignatowska, J.; Grela, K. J. Org. Chem., 2004, 69, 7748.

ArOHYield (%)ArOHYield (%)3,5-(CF3)2253,4-Cl2692,4-Cl2332-F834-CO2Me132-F-5-Me813-NO2234-Cl532-Cl284-F154-CF351

Commercially availableHighly activeFirst well defined catalystAir/moisture sensitiveImproved compatibility*

*Schrock, R.R.; Clark, D.N.; Sancho, J.; Wengrovius, J.H.; Rocklage, S.M.; Pedersen, S.F. Organometallics, 1982, 1, 1645.Listemann, M.L.; Schrock, R.R., Organometallics, 1985, 4, 74.

Highly sensitiveMust be handled under argonPrecatalyst is capable of activating nitrogenHigh reactivityGood functional group tolerance*

*Laplaza, C.E.; Odom, A.L.; Davis, W.M.; Cummins, C.C.; Protasiewicz, J.D. J. Am. Chem. Soc., 1995, 117, 4999.Furstner, A.; Mathes, C.; Lehmann, C.W. Chem. Eur. J., 2001, 7, 5299.

More efficient due to reductive recycle strategyAllows access to a variety of alkylidynes*Zhang, W.; Kraft, S.; Moore, J.S. Chem. Commun., 2003, 832.

High air and moisture resistanceIn situ generation of alkylidyne active speciesProvides reactivity and functional group tolerance of Molybdenum carbyne complexes*

*Bindl, M.; Stade R.; Heilmann, E.K.; Picot, A.; Goddard, R. Furstner, A. J. Am. Chem. Soc., 2009, 131, 9468.

High lewis acidity lowers compatibility*

abcdaminesOOPPthioethersOOPPcrown ethersOOPPthiophenesOOOPsecondary amidesOOOOpyridinesOOPP

Standard RCM*

Substrate bearing a non-terminal alkyneCatalyst compatible with substrate fuctional groupsAppropriate temperatureDriven by removal of byproduct2-Butyne requires high temperature and vacuum to removeFormation of insoluble byproducts is more effective*Zhang, W.; Moore, J.S.; J. Am. Chem. Soc., 2004, 126, 12796.

Reductive method controls the stereochemistry*

PolymerizationCross metathesisRCMTotal Synthesis/Materials*

Early examples are non-livingEffective when opening strained systems*

First exampleNon-living polymerization of cyclooctyneHigh PDI*Krouse, S.A.; Schrock, R.R. Macromolecules, 1989, 22, 2569.

eq cyclooctyneMnPDI25043006.135075004.450086007

Living polymerization*Fischer, F.R.; Nuckolls, C. Angew. Chem. Int. Ed., 2010, 49, 7257.

R1R2MnPDIHH540002BrH651002.6BrBr320001.8

Effect of phenol on living polymerizationPhenol replaces the amide ligand*Fischer, F.R.; Nuckolls, C. Angew. Chem. Int. Ed., 2010, 49, 7257.

AdditiveMnPDI2-NO2-ArOH193001.1F6-tBuOH869002.14-NO2-ArOH10200001.83,5-(CF3)2-ArOH1700001.33,5-F2-ArOH9310001.83-NO2-ArOH2480001.32-CF3-ArOH5990001.44-CF3-ArOH410002.53-CF3ArOH91700022-F-ArOH734002.33-F-ArOH304002.94-F-ArOH907002.52-naphthol524002.1phenol1620003.14-CH3-ArOH7180024-CH3O-ArOH627002.1F3-tBuOH568002.1tBuOH2010002.8(+)-menthol1200002HN(tBu)Ar1530001.7

Can be highly selectiveCan be pushed to completion by removal of 2-butyne

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Homodimerization*Furstner, A.; Mathes, C. Org. Lett., 2001, 3, 221.

Aryield3-CF3-Ph594-CN-Ph582-OMe-Ph682-CO2Me-Ph764-HCO-Ph462-thiophene0

*Kaneta, N.; Hikichi, K.; Asaka, S.; Uemaura, M.; Mori, M. Chem. Lett., 1995, 1055.

*Furstner, A.; Mathes, C. Org. Lett., 2001, 3, 221.

Aryield3-CF3-Ph704-CN-Ph702-OMe-Ph672-CO2Me-Ph624-HCO-Ph472-thiophene55

Synthesis application*Furstner, A.; Dierkes, T. Org. Lett., 2000, 2, 2463.

Synthesis application*Furstner, A.; Mathes, C. Org. Lett., 2001, 3, 221.

Allows access to high molecular weight polymersCopolymerization is possiblePolymers can be heavily conjugatedUseful for semiconducting materials*For an overview see: Bunz, U. H. F. Acc. Chem. Res., 2001, 34, 998.

Conjugated polymers*Kloppenburg, L.; Song, D.; Bunz, U.H.F. J. Am. Chem. Soc., 1998, 120, 7973.See also: Zhang, W.; Moore, J.S. Macromolecules, 2004, 37, 3973.Brizius, G.; Kroth, S.; Bunz, U.H.F. Macromolecules, 2002, 35, 5317.

RPnPDIHexyl943.5(+)-(CH2)2CHMe(CH2)3CH(CH3)21502.5OCH2CH2CH(CH3)2152.7

RPnPDI3,7-dimethyloctyl313.1dodecyl242.32-ethylhexyl263.7

Copolymers*Brizius, G.; Kroth, S.; Bunz, U.H.F. Macromolecules, 2002, 35, 5317.

RxyPnPDIdodecyl0.50.5694.7dodecyl0.20.81143

Allows access to the Z olefin via subsequent metathesis/reduction reactionsUseful for controlling the geometry of macrocyclic products*

*Furstner, A.; Guth, O.; Rumbo, A.; Seidel, G. J. Am. Chem. Soc. 1999, 121, 11108.

*Furstner, A.; Guth, O.; Rumbo, A.; Seidel, G. J. Am. Chem. Soc. 1999, 121, 11108.

Alkyne used to give access to the Z isomer*Furstner, A.; Grela K. Angew. Chem. Int. Ed., 2000, 39, 1234.

Alkyne used to form exclusively the E isomer*Furstner, A.; Bonnekessel, M.; Blank, J. T.; Radkowski, K.; Seidel, G.; Lacombe, F.; Gabor, B.; Mynott, R. Chem. Eur . J., 2007, 13, 8762.

*Furstner, A.; Castanet, A.-S.; Radkowski, K.; Lehmann, C. W. J. Org. Chem. 2003, 68, 1521.

*Benson, S.; Collin, M-P.; Arlt, A.; Gabor, B.; Goddard, R.; Furstner, A. Angew. Chem. Int. Ed., 2011, 50, 8739.

Requires high dilution to be efficientEarly example shown0.19 M*Ge, P.-H.; Fu, W.; Herrmann, W.A.; Herdtweck, E.; Campana, C.; Adams, R.D.; Bunz, U.H.F. Angew. Chem. Int. Ed., 2000, 39, 3607.

*Pschirer, N.G.; Fu, W.; Adams, R.D.; Bunz, U.H.F Chem. Comm., 2000, 87.

Byproduct precipitates to drive the reactionMajor increase in isolated yieldNo need to remove butyne at high temperature*Zhang, W.; Moore, J.S.; J. Am. Chem. Soc., 2004, 126, 12796.

Allows selective access to E or Z olefinsSelective ring closing in the presence of alkenesAlkyne can be used to perform many synthetically useful transformationsGives easy access to useful heavily conjugated materials*

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