Reductions of activated carbonyl compounds with chiral-bridged 1,4-dihydropyridines. An investigation of scope and structural effects
作者:Auke G. Talma、Patrick Jouin、Johannes G. De Vries、C. B. Troostwijk、Gerard H. Werumeus Buning、Jan K. Waninge、Johnny Visscher、Richard M. Kellogg
DOI:10.1021/ja00299a038
日期:1985.6
bridged macrocyclic 1,4-dihydropyridines (7) have been synthesized by starting from valine, alanine, phenylglycine, phenylalanine, and proline. Various bridges of different compositions, lengths, and shapes have been incorporated. All these bridged compounds in a nonprotic solvent like CH3CN in the presence of a stoichiometric amount of Mg(ClO4)2·1.5H2O reduce activated carbonyl compounds to the corresponding
已经制备了一系列手性桥接大环 1,4-二氢吡啶,并研究了这些化合物对映选择性还原的潜力。典型的合成以吡啶-3-5-二羧酸 (9, W = OH) 开始,它与 (S)-缬氨酸偶联以最终生成双偶联产物 10 (X = OH)。将其转化为双(羧酸铯)并使其在二甲基甲酰胺 (DMF) 溶液中以 10-2 至 5 × 10-3 M 的浓度与 1,5-二溴-3-氧戊烷反应。大环 11a (R = CH(CH3)2) 的产率为 48%。随后用 CH3I/Mg(ClO4)2·1.5H2O 甲基化生成高氯酸吡啶鎓,然后用 Na2S2O4 将其还原为 1,4-二氢吡啶。以这种方式,从缬氨酸、丙氨酸、苯甘氨酸、苯丙氨酸和脯氨酸。各种不同成分、长度和形状的桥都被合并了。在化学计量的 Mg(ClO4)2·1.5H2O 存在下,所有这些桥接化合物在非质子溶剂如 CH3CN 中将活性羰基化合物还原为相应的醇;形成相应的