Nicholas Greeves
University of Liverpool
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Featured researches published by Nicholas Greeves.
Tetrahedron Letters | 2002
Helen C. Aspinall; James S Bissett; Nicholas Greeves; Daniel Levin
Abstract Lanthanum triflate–benzoic acid catalyses the in situ formation and allylation of various imines from aldehydes and an aromatic amine.
Tetrahedron Letters | 1999
Helen C. Aspinall; Nicholas Greeves; Peter M. Smith
Abstract Complexes formed between lanthanide trichlorides and 2,6-bis( substituted -2-oxazolin-2-yl)pyridine (pybox) ligands are effective catalysts for the enantioselective addition of trimethylsilylcyanide (TMSCN) to a range of aldehydes.
Tetrahedron Letters | 1998
Helen C. Aspinall; Nicholas Greeves; Edward G. McIver
Abstract Addition of one equivalent of benzoic acid greatly enhances the efficiency of our ytterbium triflate catalyzed allylation of aldehydes with allyltributyltin in acetonitrile. Crucial modifications to reaction conditions result in a dramatically increased rate at remarkably low catalyst loading.
Tetrahedron Letters | 1994
Helen C. Aspinall; Andrew F. Browning; Nicholas Greeves; Paul Ravenscroft
Abstract Ytterbium triflate has been found to be an excellent Lewis acid catalyst for the reaction of aldehydes with allyltributylstannane.
Tetrahedron Letters | 2002
Helen C. Aspinall; James S Bissett; Nicholas Greeves; Daniel Levin
Abstract Lanthanum triflate in combination with benzoic acid catalyses the allylation of aldehydes at low catalyst loading, without the need to activate the catalyst in advance.
Tetrahedron Letters | 1992
Nicholas Greeves; Lisa Lyford
Abstract Sonication of anhydrous CeCl 3 in tetrahydrofuran facilitates rapid preparation of organocerium reagents.
Tetrahedron Letters | 1997
Helen C. Aspinall; Nicholas Greeves; Wai-Man Lee; Edward G. McIver; Peter M. Smith
Abstract 15-crown-5 greatly facilitates Williamson ether synthesis when sodium hydride base is used in THF solvent. This mild yet versatile procedure has been employed in the synthesis of new homochiral polyether ligands and bis-allylic ethers which are inaccessible by conventional methods.
Journal of Organometallic Chemistry | 2002
Helen C. Aspinall; Nicholas Greeves
This paper reviews our work with enantioselective lanthanide reagents and catalysts for organic synthesis. Heterometallic reagents M3[Ln(binol)3 ]( M=Li; Ln=lanthanide; H2binol= binaphthol) mediate the addition of RLi to aldehydes with ee’s of up to 84%. Structural studies have been carried out where M = Li or Na, Ln= Eu, Y or Yb and with enantiomerically pure or racemic binol. There are important differences in coordination chemistry dependent on the ionic radius of M and Ln. [LnCl3(pybox)2] are effective catalysts for the silylcyanation of aldehydes, giving ee’s of up to 89% under convenient reaction conditions. Structural studies have been undertaken on [Ln(OTf)3(Pr i pybox)2] for Ln= La, Eu or Yb.
Tetrahedron Letters | 1984
Antony D. Buss; Nicholas Greeves; Daniel Levin; Paul Wallace; Stuart Warren
Abstract Single isomers ( E or Z ) of homoallylic and higher alcohols can be synthesised from ω-hydroxyalkyldiphenylphosphine oxides and aldehydes, or from alkyldiphenylphosphine oxides and lactones
Tetrahedron Letters | 1996
Nicholas Greeves; J.Elizabeth Pease; Martin Charles Bowden; Stephen Martin Brown
Abstract A range of TADDOL organocerium reagents have been prepared and the effect of TADDOL structure on their enantioselective addition to aldehydes has been studied.