1224225-80-2Relevant academic research and scientific papers
Phosphine-catalyzed asymmetric synthesis of β-lactones from disubstituted ketenes and aldehydes
Chen, Shi,Mondal, Mukulesh,Ibrahim, Ahmad A.,Wheeler, Kraig A.,Kerrigan, Nessan J.
, p. 4920 - 4929 (2014/06/23)
In this article we describe a general catalytic procedure for the formation of β-lactones bearing two stereogenic centers, from disubstituted ketenes and achiral aldehydes. BINAPHANE was found to display excellent enantioselectivity (≤90% ee for eight examples) and good diastereoselectivity (≤90:10 for 13 examples) in catalyzing the formation of β-lactones bearing two stereogenic centers from achiral aldehydes (both aromatic and aliphatic) and alkylarylketenes or dialkylketenes. A preference for formation of the trans diastereomer was observed in these reactions. For those reactions where BINAPHANE failed as a catalyst, tri-n-butylphosphine was found to be an effective achiral nucleophilic catalyst, effecting good yield and diastereoselectivity in racemic β-lactone formation. Evidence for the involvement of phosphonium enolate intermediates in the reaction mechanism was obtained through reaction monitoring by 31P NMR spectroscopy and by comparison with previously characterized intermediates observed in the phosphine-catalyzed ketene homodimerization reaction.
Phosphine-catalyzed asymmetric synthesis of β-lactones from arylketoketenes and aromatic aldehydes
Mondal, Mukulesh,Ibrahim, Ahmad A.,Wheeler, Kraig A.,Kerrigan, Nessan J.
supporting information; experimental part, p. 1664 - 1667 (2010/09/05)
In this paper, the development of a chiral phosphine-catalyzed formal [2 + 2] cycloaddition of aldehydes and ketoketenes that provides access to a variety of highly substituted β-lactones (14 examples) is reported. The BINAPHANE catalytic system displays excellent enantioselectivity (seven examples with ee ≥90%) and high diastereoselectivity favoring formation of the trans-diastereomer (nine examples with dr ≥90:10).
