ACKNOWLEDGEMENTS
The authors thank AEC1 Ltd for a Post-graduate Fellowship (M L.B.), Rhodes Unlvurs=ty and the Foundat=on for
Research Development for generous financial support, and Dr
assistance w=th EPR spectroscopy
C McClelland (Umvers=ty of Port Ehzabeth) for
REFERENCES AND NOTES
t
Applications of thts reactmn, whmh was first reported by Bayhs, A D ; Hdlman, M E D [German Patent
155113 (1972)] have been recently revmwcd by Drewes, S E ; Roos, G H P Yotrahedron, 1988, 4,1, 4653
2
2
Drewes, S E, Emshe, N D. J. Chem. S o c . , P e r k i n Trans. l, 1982, 2079
3
A.m_cer, F,Dre~es~SE,HooIe, R F A Kaye, PT~,Pttchford, A T J. Chem. S o c . , P e r k z n Trans. 2,
1985, 2713
4
5
Ame.~,F;DreweNSE,Housto~t-McM.J-llatt, M S , K a y % P . T S . A f r . J . Ctte~, 1~N~, 39, 57
Hoffmann, H.M R.; Robe, J. g e l re. ChAin. Auto, 1984, 67, 413 and ltoflmann, H M R, Robe, J
J. Org. Che~, 1985, 50, 3849
6
7
Ameer~ F ~ Drewe~. S E~ Freese, &, Kaye, P T S y a t h . Commur~ 198& 18, 495
The aldehydes 1 and acrylate esters 2 were distilled prior to use All reactants were thcrmostatted, prmr to
mtrang, at the probe temperature (37°C) of the Perkm Elmer RI2A 60 Mt-lz NMR spectrometer used to follow the
rcactmns In a typmal procedure, pyndme-4-carboxaldehydc (0 107 g, 1 0 mmol), 3-hydmxyqumuclidlne (0 I)1/7 g,
0
06 retool) and CDCI3 (0 550 g) were weighed rote a 1 ml flask and healed to probe temperature After
cqmhbration, methyl acrylate (0 086 g, 1 0 retool) was added (t = to) and Ihe reaction mixture transtcrred to ,in
NMR: ~o'b'e T~e mea'sttred rate ,:vJa~t~n~s {Tabl'e l) refJrewent, m eater cas¢~, th'c arc'art of t~o dc'tcrrrrmatroa~ ~rucb
agreed w=thm acceptable hmats
8
Plots of l/(a-x) versus t (for a = b) or In (a-x)/(b-x) versus t (for a ;~ b) (where a amt b correspond to the mlt=al
concentrations of aldehyde 1 and acrylate ester 2 respectively, and x corresponds to the conccntratum of product 3
at time t) gave essentially strmght hnes over the initm150-70% of each reaction, with slopes equal to ka or ka(a-b)
respect=rely
9
1
In some instances, data-point scatter and curvature was more pronounced, but linear regression analysis of points
corresponding to at least 50% completmn st~ll afforded acceptable correlation coefficmnts (_ >_ 0 99)
The possibd=ty of an electron transfer process, involving the 3°amine, was explored by conducting a reactmn
0
(
(
comparable to entry 1, Table 1) m the probe ofa Varian E-Line Century EPR spectrometer operating at 9 5 Gblz
magnet=e field - 3360 G, field scan " 1000 G) Three scans, using various gain, modular=on amphtudc and
microwave power settings laded to provide any evidence for the presence of ra&cal spc~cs
II
Deutermtlon of 3-hydroxyqumuclidme was effected by stirring 3-bydroxyqtunuch&nc (1 g) m CD3OD (1 ml) for
2
0 mm, evaporating the solvent and repeating the process untd no hydroxyl signal was v=stble m the tH NMR
spectrum of the deuter~ated product.
(
R e c e i v e d m UK 23 July 1991)