Assembled Dendritic Titanium Catalysts for Enantioselective Hetero-Diels–Alder Reaction of Aldehydes with Danishefsky's Diene
作者:Baoming Ji、Yu Yuan、Kuiling Ding、Jiben Meng
DOI:10.1002/chem.200305286
日期:2003.12.15
titanium-catalyzed hetero-Diels-Alderreaction of Danishefsky's diene with aldehydes. These reactions afforded the corresponding 2-substituted 2,3-dihydro-4H-pyran-4-ones in quantitative yields and with excellent enantioselectivities (up to 97.2 % ee). The disposition of the dendritic wedges and the dendron size in the ligands were found to have significant impact on the enantioselectivity of the reaction. The recovered
Enantiopure (P)- and (M)-3,14-bis(o-hydroxyaryl)tetrahydrobenzo[5]helicenediols and their helicene analogues: Synthesis, amplified circularly polarized luminescence and catalytic activity in asymmetric hetero-Diels–Alder reactions
作者:Lei Fang、Meng Li、Wei-Bin Lin、Chuan-Feng Chen
DOI:10.1016/j.tet.2018.10.047
日期:2018.12
exhibited more intense CPL with amplified glum, which might be attributed to the more rigid structure of PhOH-[5]HOLs. However, rigid PhOH-[5]HOLs was less effective in the catalytic asymmetrichetero-Diels–Alder (HAD) reactions than those of ArOH-H[5]HOLs with the flexible tetrahydro[5]helicene backbone that could adjust conformation to suit the substrates. Therefore, the helical chirality amplification
<i>cis</i>-2,5-Diaminobicyclo[2.2.2]octane, a New Scaffold for Asymmetric Catalysis via Salen−Metal Complexes
作者:James D. White、Subrata Shaw
DOI:10.1021/ol2007378
日期:2011.5.6
A new C2 symmetric salen scaffold based on cis-2,5-diaminobicyclo[2.2.2]octane has been synthesized that forms complexes with a wide range of metals. The chromium(III) complex is shown to catalyze the hetero-Diels−Alder reaction and the Nozaki−Hiyama−Kishi reaction with high efficiency and excellent stereoselectivity.