1065515-31-2Relevant articles and documents
Organocatalyzed conjugate addition of carbonyl compounds to nitrodienes/nitroenynes and synthetic applications
Belot, Sebastien,Quintard, Adrien,Krause, Norbert,Alexakis, Alexandre
supporting information; experimental part, p. 667 - 695 (2010/06/22)
The purpose of this study is to point out the synthetic utility of a new class of Michael acceptors (nitrodienes and nitroenynes). The highly enantioselective organocatalytic Michael addition of carbonyl compounds to these functionalized nitroolefins has been carried out in the presence of (S)-diphenylprolinol silyl ether to achieve some interesting building blocks in high selectivities. The adducts thus obtained can be easily converted by taking advantage of the corresponding unsaturated carbon-carbon bond. In presence of the double bond, metathesis or electrophilic activation could be carried out whereas in the presence of the triple bond electrophilic acti-vation could be conducted. We thus focused on a gold-catalyzed cyclization of the bis-homopropargylic alcohol to afford the corresponding substituted tetrahydrofuran. Then, we also demonstrated that organic and gold catalysts were compatible in a one-pot process. Indeed, we developed a one-pot enantioselective organocatalytic Michael addition to a nitroenyne followed by a gold-catalyzed acetalization/cyclization to achieve tetrahydrofuranyl ethers in high diastereoand enantioselectivities with excellent yields.
Enantioselective organocatalytic conjugate addition of aldehydes to nitrodienes
Belot, Sebastien,Massaro, Assunta,Tenti, Alice,Mordini, Alessandro,Alexakis, Alexandre
supporting information; experimental part, p. 4557 - 4560 (2009/05/11)
(Chemical Equation Presented) The asymmetric organocatalyzed Michael addition of aldehydes to α,β-γ,δ-unsaturated nitro compounds has been accomplished using only 5 mol % of (S)-diphenylprolinol silyl ether and 2 equiv of aldehyde in a mixture of ethanol and water (5% v/v). The Michael adducts were obtained in good yields, diastereoselectivities up to 94/6, and ee's up to 99%. This process provides synthetically useful compounds which can easily lead to more complex molecules, as exemplified with substituted tetrahydropyran or cyclohexene.
