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DOI: 10.1055/s-0032-1317905
Frustrated Lewis Pairs for Catalytic Hydrogenation of Allenes and Alkenes
Publication History
Publication Date:
17 December 2012 (online)
Significance
The Alcarazo group reports a frustrated Lewis pair (FLP)-catalyzed hydrogenation reaction of electron-poor allenes and alkenes. The reduced products were obtained with good to excellent yield and high chemoselectivity by employing DABCO–B(C6F5)3 as a catalyst pair (10–15 mol%).
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Comment
To overcome the inherent reactivity of electron-rich allenes to cyclize to Friedel–Crafts products 1 in the presence Brønsted acids and/or Lewis acids, the authors employ electron-poor substrates to facilitate FLP-catalyzed hydrogenation to the desired product 2. According to the mechanistic studies, [DABCO–H]+ might act as a hydrogen-bond donor to activate the substrate. The hydride from the borohydride is transferred via 1,4-addition.
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