10.1021/jo991011h.s003 Alan C. Spivey Alan C. Spivey Tomasz Fekner Tomasz Fekner Sharon E. Spey Sharon E. Spey Harry Adams Harry Adams Configurationally Stable Biaryl Analogues of 4-(Dimethylamino)pyridine:  A Novel Class of Chiral Nucleophilic Catalysts American Chemical Society 1999 biaryl axes methyl DMAP rotation pyridine core 16 configurationally chiral nucleophilic catalysts Biaryls 55 Chiral Nucleophilic Catalysts biaryls 31 Comparative HPLC studies Compounds 55 Novel Class biaryl axis Ar Configurationally Stable Biaryl Analogues ambient temperature atropisomeric analogues acyl transfer pyrrolidino substituent ortho novel class 1999-12-04 00:00:00 Journal contribution https://acs.figshare.com/articles/journal_contribution/Configurationally_Stable_Biaryl_Analogues_of_4-_Dimethylamino_pyridine_A_Novel_Class_of_Chiral_Nucleophilic_Catalysts/3719196 A short synthetic approach toward a novel class of chiral nucleophilic catalysts, the dissymmetry of which stems from restricted rotation about an Ar−Ar bond, has been developed. The key steps of the synthesis include preparation of a nucleophilic 1-methyl-2-pyrrolino[3,2-<i>c</i>]pyridine core <b>16</b> by <i>ortho</i>-lithiation and creation of the biaryl axes via Suzuki cross-coupling reactions. Comparative HPLC studies of racemization for configurationally labile biaryls <b>31</b>, <b>38</b>, and <b>43</b> containing 1-methyl-2-pyrrolino[3,2-<i>c</i>]pyridine, 4-(dimethylamino)pyridine, and 4-(1-pyrrolidino)pyridine cores, respectively, have demonstrated that a pyrrolidino substituent <i>ortho</i> to the biaryl axis is optimal for slowing Ar−Ar rotation. Biaryls containing all three cores have been shown to retain DMAP-like catalytic activity in the acylation of a hindered alcohol. Biaryls <b>55</b> and <b>56</b>, which are configurationally stable at ambient temperature, have also been prepared via modification of configurationally labile derivatives. Compounds <b>55</b> and <b>56</b> in optically pure form should provide a useful starting point for studies on catalytic asymmetric acyl transfer using atropisomeric analogues of DMAP.