01433nas a2200169   4500008004100000022001400041245006300055210005900118260000800177300001400185490000700199520089300206100002401099700002501123700002401148856009101172       2019                        eng d  a1523-706000aEnantioselective formal total synthesis of (-)-quinagolide0 aEnantioselective formal total synthesis of quinagolide  cNOV  a9089-90930 v213 a<p>The enantioselective formal total synthesis of (-)-quinagolide has been accomplished in a linear sequence of 8 purification steps from pyridine. The key steps are (a) organocatalyzed Diets-Alder reaction for fixing all three stereocenters on piperidine ring; (b) protecting group enabled deoxygenation of isoquinuclidine skeleton under Birch reduction condition; (c) Lewis acid (TiCl4) catalyzed intramolecular Friedel-Crafts cyclization of dicarboxylic acid; and (d) one-pot diastereoselective ketone reduction-intramolecular cyclization to form oxazolidinone which enables trans-geometry installation. During the course of the synthesis, an interesting reductive cleavage of the C-N bond in the electron-deficient isoquinuclidine skeleton under the Birch reduction conditions has been observed. This is the first synthetic effort to access the core skeleton of (-)-quinagolide.</p>
1 aChavan, Subhash, P.1 aKadam, Appasaheb, L.1 aGonnade, Rajesh, G.  uhttps://library.ncl.res.in/content/enantioselective-formal-total-synthesis-quinagolide