Grignon-Dubois

Grignon-Dubois and coworkers have shown that reduction of a quinoline using zinc and acetic acid in THF gives the dimeric compound 3-177 via intermediate 3-176 (Scheme 3.47) [70J. Usually, a mixture of the syn- and anti-products is formed the substituent has some influence on the regioselectivity of the dimerization and cydization step. With R = H and R = 6-Me, only the benzazepine 3-177 were produced, by a head-to-head dimerization. 

Grignon-Dubois M, Rezzonico B, Usubillaga A, Vojas LB. Isolation of Plumieride from Plumeria inodora. Chemistry of Natural Compounds 2005 41(6) 730-731. 

The coupling constant values and sometimes also their relative signs can be obtained by a detailed analysis of the SPT spectra using simulation programs90,91. The procedure as well as the basis of the SPT experiment is described by Grignon-Dubois and Laguerre90 very lucidly, especially for a non-specialist the self-explanatory Figure 10 is reproduced from that source. 

FIGURE 10. 29Si SPT NMR spectra (measured and simulated) of cyclopropane derivatives. Reproduced with permission of M. Grignon-Dubois from Reference 90... 

Lor a precedent of the trichloromethylation step, see Grignon-Dubois M, Diaba F, Grellier-Marly M-C (1994) Synthesis 800. 

M. Grignon-Dubois, J. Dunogues and R. Galas, Can. J. Chem., 59, 802 (1981) and references cited therein. 

Grignon-Dubois, M. Dunogues, J. Ahra, M. Reel Trav. Chim. Pays-Bas 1988, 707, 216. Banwell, M.G. Halton, B. Aust. J. Chem. 1980, 33, 2673. 

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