Ramachary Dhevalapally B, Kishor Mamillapalli
School of Chemistry, University of Hyderabad, Hyderabad-500 046, India.
Org Biomol Chem. 2008 Nov 21;6(22):4176-87. doi: 10.1039/b807999d. Epub 2008 Aug 12.
A direct amino acid-catalyzed chemo- and enantioselective process for the double cascade synthesis of highly substituted 2-alkyl-cyclopentane-1,3-diones, 2-alkyl-3-methoxy-cyclopent-2-enones and Hajos-Parrish (H-P) ketone analogs is presented via reductive alkylation chemistry. For the first time, we have developed a single-step alkylation of cyclopentane-1,3-dione with aldehydes/ketones and a Hantzsch ester through an organocatalytic reductive alkylation strategy. A direct combination of amino acid-catalyzed cascade olefination-hydrogenation and cascade Robinson annulations of cyclopentane-1,3-dione, aldehydes/ketones, a Hantzsch ester and methyl vinyl ketone furnished the highly functionalized H-P ketone analogues in good to high yields and with excellent enantioselectivities. Many of the reductive alkylation products have shown direct applications in pharmaceutical chemistry.
通过还原烷基化化学方法，介绍了一种直接的氨基酸催化的化学和对映选择性过程，用于双级联合成高度取代的2-烷基环戊烷-1,3-二酮、2-烷基-3-甲氧基环戊-2-烯酮和哈约什-帕里什（H-P）酮类似物。我们首次通过有机催化还原烷基化策略，开发了环戊烷-1,3-二酮与醛/酮和汉斯酯的单步烷基化反应。氨基酸催化的级联烯烃化-氢化反应与环戊烷-1,3-二酮、醛/酮、汉斯酯和甲基乙烯基酮的级联罗宾逊缩环反应直接结合，以良好至高的产率和优异的对映选择性得到了高度官能化的H-P酮类似物。许多还原烷基化产物已在药物化学中显示出直接应用。
