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Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts

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Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts. / Allingham, M.T.; Bennett, E.L.; Davies, Deiniol et al.
In: Tetrahedron, Vol. 72, No. 4, 28.01.2016, p. 496-503.

Research output: Contribution to journal › Article › peer-review

HarvardHarvard

Allingham, MT, Bennett, EL, Davies, D, Harper, PM, Howard-Jones, AG, Mehdar, YT, Murphy, PJ, Thomas, D, Caulkett, PW, Potter, D, Lam, CM & O'Donoghue, AC 2016, 'Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts', Tetrahedron, vol. 72, no. 4, pp. 496-503. https://doi.org/10.1016/j.tet.2015.11.058

APA

Allingham, M. T., Bennett, E. L., Davies, D., Harper, P. M., Howard-Jones, A. G., Mehdar, Y. T., Murphy, P. J., Thomas, D., Caulkett, P. W., Potter, D., Lam, C. M., & O'Donoghue, A. C. (2016). Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts. Tetrahedron, 72(4), 496-503. https://doi.org/10.1016/j.tet.2015.11.058

CBE

Allingham MT, Bennett EL, Davies D, Harper PM, Howard-Jones AG, Mehdar YT, Murphy PJ, Thomas D, Caulkett PW, Potter D, et al. 2016. Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts. Tetrahedron. 72(4):496-503. https://doi.org/10.1016/j.tet.2015.11.058

MLA

Allingham, M.T. et al. "Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts". Tetrahedron. 2016, 72(4). 496-503. https://doi.org/10.1016/j.tet.2015.11.058

VancouverVancouver

Allingham MT, Bennett EL, Davies D, Harper PM, Howard-Jones AG, Mehdar YT et al. Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts. Tetrahedron. 2016 Jan 28;72(4):496-503. Epub 2015 Nov 30. doi: 10.1016/j.tet.2015.11.058

Author

Allingham, M.T. ; Bennett, E.L. ; Davies, Deiniol et al. / Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts. In: Tetrahedron. 2016 ; Vol. 72, No. 4. pp. 496-503.

RIS

TY - JOUR

T1 - Synthesis, applications and mechanistic investigations of C2 Symmetric Guanidinium salts

AU - Allingham, M.T.

AU - Bennett, E.L.

AU - Davies, Deiniol

AU - Harper, P.M.

AU - Howard-Jones, A.G.

AU - Mehdar, Y.T.

AU - Murphy, P.J.

AU - Thomas, Dafydd

AU - Caulkett, P.W.

AU - Potter, D.

AU - Lam, C.M.

AU - O'Donoghue, A.C.

PY - 2016/1/28

Y1 - 2016/1/28

N2 - A range of guanidinium catalysts was prepared in 6 or 7 synthetic steps and applied to the phase transfer alkylation of a glycinate Schiff’s base in 21-86% ee as well as the phase transfer epoxidation of some chalcones in 85-94% ee. Using a spectrophotometric method, pKa values in the range 13.2-13.9 in DMSO have been determined for some of the catalysts highlighting an increase in basicity relative to achiral tetramethylguanidine (pKa = 13.0) and a mechanism involving the protonated guanidinium ion as a phase transfer catalyst is proposed. The use of two of the catalysts for the addition of nucleophiles in Michael addition reactions was investigated and both were found to be effective catalysts. A counterion effect was apparent in these reactions, but no enantioselectivity was observed.

AB - A range of guanidinium catalysts was prepared in 6 or 7 synthetic steps and applied to the phase transfer alkylation of a glycinate Schiff’s base in 21-86% ee as well as the phase transfer epoxidation of some chalcones in 85-94% ee. Using a spectrophotometric method, pKa values in the range 13.2-13.9 in DMSO have been determined for some of the catalysts highlighting an increase in basicity relative to achiral tetramethylguanidine (pKa = 13.0) and a mechanism involving the protonated guanidinium ion as a phase transfer catalyst is proposed. The use of two of the catalysts for the addition of nucleophiles in Michael addition reactions was investigated and both were found to be effective catalysts. A counterion effect was apparent in these reactions, but no enantioselectivity was observed.

U2 - 10.1016/j.tet.2015.11.058

DO - 10.1016/j.tet.2015.11.058

M3 - Article

VL - 72

SP - 496

EP - 503

JO - Tetrahedron

JF - Tetrahedron

SN - 0040-4020

IS - 4

ER -