Asymmetric Flow Reactions Catalyzed by Immobilized Diphenylprolinol Alkyl Ether: Michael Reaction and Domino Reactions
Flow reactions using an immobilized diphenylprolinol alkyl ether catalyst 2 were investigated in three reactions of α,β‐unsaturated aldehydes and nitroalkanes such as nitromethane 3, nitroethanol 10, and nitroalkane 11, bearing two carbonyl groups. Whereas reactions using the corresponding monomer c...
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Published in | Chemistry, an Asian journal Vol. 17; no. 14; pp. e202200314 - n/a |
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Main Authors | , , |
Format | Journal Article |
Language | English |
Published |
Germany
Wiley Subscription Services, Inc
15.07.2022
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Subjects | |
Online Access | Get full text |
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Summary: | Flow reactions using an immobilized diphenylprolinol alkyl ether catalyst 2 were investigated in three reactions of α,β‐unsaturated aldehydes and nitroalkanes such as nitromethane 3, nitroethanol 10, and nitroalkane 11, bearing two carbonyl groups. Whereas reactions using the corresponding monomer catalyst diphenylprolinol silyl ether 1 were slow, fast reactions were found with the immobilized polymer catalyst 2 in a batch system, and the latter was then applied to a flow system. In the Michael reaction of nitromethane 3, the polymer catalyst showed high reactivity in the initial 30 h and then decreased gradually. Good overall yield (72%) and turnover number (TON, 495) were obtained for a 60 h flow reaction, and the enantioselectivity of the product was excellent throughout. The TONs of domino reactions of nitroethanol 10 and nitroalkane 11, with two carbonyl groups, were 48 and 81, respectively.
Immobilized diphenylprolinol alkyl ether catalyst was found to be effective for the flow reactions. Three flow reactions were examined. Good overall yield (72%), excellent enantioselectivity (93% ee), and good turnover number (TON, 495) were obtained for a 61 h flow Michael reaction of nitromethane and cinnamaldehyde. |
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ISSN: | 1861-4728 1861-471X |
DOI: | 10.1002/asia.202200314 |