Department of Chemistry, University of Miami, 1301 Memorial Drive, Coral Gables, FL 33146, USA.
Molecules. 2013 Aug 19;18(8):9982-98. doi: 10.3390/molecules18089982.
Helical-chiral double hydrogen bond donor catalysts promote the nitroalkene Diels-Alder reaction in an enantio- and periselective manner. This represents the first asymmetric catalytic nitroalkene Diels-Alder reaction via LUMO-lowering catalysis. To gain an insight into this new process, the substrate scope of our catalyst was investigated by exploiting readily available 5-substituted pentamethylcyclopentadienes. The catalyst was found to tolerate dienes with different steric demands as well as dienes substituted with heteroatoms. The synthetic utility of 5-substituted pentamethylcyclopentadienes is rather limited, and thus we have developed a three-step route to 1,4,5,5-tetrasubstituted cyclopentadienes from commercially available ketones.
手性螺旋双氢键供体催化剂以对映选择性和优势选择性促进硝烯 Diels-Alder 反应。这代表了首例通过降低最低未占分子轨道（LUMO）催化的不对称催化硝烯 Diels-Alder 反应。为了深入了解这一新过程，我们利用易得的 5-取代的五甲基环戊二烯来研究我们的催化剂的底物范围。发现该催化剂可以容忍具有不同空间需求的二烯以及取代有杂原子的二烯。5-取代的五甲基环戊二烯的合成用途相当有限，因此我们开发了一种从商业可得的酮合成 1,4,5,5-四取代环戊二烯的三步路线。
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