Ranaivoarimanana Naliharifetra Jessica, Habaki Xin, Uto Takuya, Kanomata Kyohei, Yui Toshifumi, Kitaoka Takuya
Department of Agro-Environmental Sciences, Graduate School of Bioresource and Bioenvironmental Sciences, Kyushu University Fukuoka 819-0395 Japan
Organization for Promotion of Tenure Track, University of Miyazaki Miyazaki 889-2192 Japan.
RSC Adv. 2020 Oct 8;10(61):37064-37071. doi: 10.1039/d0ra07412h. eCollection 2020 Oct 7.
Cellulose nanofibers obtained from wood pulp by TEMPO-mediated oxidation acted as a chiral enhancer in direct aldol reactions of 4-nitrobenzaldehyde and cyclopentanone with ()-proline as an organocatalyst. Surprisingly, catalytically inactive TEMPO-oxidized cellulose nanofibers enriched the (,)-enantiomer in this reaction, affording 89% ee in the form with a very high yield (99%). Conversely, nanocellulose-free ()-proline catalysis resulted in poor selectivity (64% ee, form) with a low yield (18%). Green organocatalysis occurring on nanocellulose solid surfaces bearing regularly aligned chiral carbons on hydrophobic crystalline facets will provide new insight into asymmetric synthesis strategies for interfacial catalysis.
通过TEMPO介导的氧化从木浆中获得的纤维素纳米纤维，在以（）-脯氨酸作为有机催化剂的4-硝基苯甲醛与环戊酮的直接羟醛反应中充当手性增强剂。令人惊讶的是，催化惰性的TEMPO氧化纤维素纳米纤维在该反应中富集了（，）-对映体，以非常高的产率（99%）得到了89% ee的形式。相反，无纳米纤维素的（）-脯氨酸催化导致选择性较差（64% ee，形式）且产率较低（18%）。在疏水结晶面上带有规则排列的手性碳的纳米纤维素固体表面上发生的绿色有机催化，将为界面催化的不对称合成策略提供新的见解。
