- Aluminum chelates supported by β-quinolyl enolate ligands: Synthesis and ROP of ?-CL
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Treatment of tautomers of β-quinolyl ketone-enaminones 1a-6a with AlMe3 afforded β-quinolyl enolato dialkylaluminium complexes LAlMe21b-6b (L = [(2-C9H6N)-CHC(R)-O-], R = CH3 (1b), tBu (2b), Ph (3b), o-tolyl (4b), p-tolyl (5b), p-OMePh (6b)), respectively. 2b reacted with benzyl alcohol to generate the corresponding LAl(OBn)2 complex 2c. Complexes 1b-6b and 2c were characterized by 1H and 13C NMR spectroscopy, elemental analyses and single crystal X-ray diffraction analyses. All complexes were tested as catalyst precursors for ring-opening polymerization of ?-caprolactone (?-CL). The results indicated that LAlMe2 (1b-6b) exhibited good activity towards the ROP of ?-CL in the presence of benzyl alcohol at 80 °C, and LAl(OBn)22c exhibited higher catalytic activity in the absence of alcohol than 1b-6b for the ROP of ?-CL. However, both polymerizations were less controlled. Kinetic studies showed that the polymerization reaction catalyzed by 1b-6b and 2c proceeded with first-order dependence on the monomer and took place through coordination-insertion.
- Wang, Peng,Hao, Xiaomin,Cheng, Jianhua,Chao, Jianbin,Chen, Xia
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p. 9088 - 9096
(2016/06/15)
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- Asymmetric tandem reduction of 2-(aroylmethyl)quinolines with phosphine-free Ru-TsDPEN catalyst
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The phosphine-free ruthenium complex containing chi-ral N-(p-toluenesulfonyl)-1,2-diphenylethylenediamine (TsDPEN) showed excellent stereoselectivity in the tandem asymmetric reduction of 2-(aroylmethyl) quinolines. The reaction involves transfer hydrogenation of aromatic ketones and hydrogenation of quinolines, giving 1,2,3,4-tetrahydroquinoline derivatives with up to 99% ee and 95:5 dr. Georg Thieme Verlag Stuttgart · New York.
- Wang, Tianli,Ouyang, Guanghui,He, Yan-Mei,Fan, Qing-Hua
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supporting information; experimental part
p. 939 - 942
(2011/06/17)
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