lithium amides by oxidation with simple ketone oxidants, are readily alkylated with a range of enolates to provide mono- and polycyclic β-aminoketones in a single operation, including the natural product (±)-myrtine. Nitrile anions also serve as competent nucleophiles in these transformations, which are promoted by BF3 etherate. β-Aminoesters derived from esterenolates can be converted to the corresponding
Asymmetric synthesis of Sedum alkaloids via lithium amide conjugate addition
作者:Stephen G. Davies、Ai M. Fletcher、Paul M. Roberts、Andrew D. Smith
DOI:10.1016/j.tet.2009.09.104
日期:2009.12
Conjugateaddition of lithium (R)-N-allyl-N-(α-methylbenzyl)amide or lithium (R)-N-but-3-enyl-N-(α-methylbenzyl)amide to an alkyl hexa-2,4-dienoate or alkyl hepta-2,6-dienoate, followed by ring-closing metathesis of the olefin functionalities within the resultant β-amino ester, generates a range of diastereoisomerically pure azacycles in good yield. These homochiral templates are readily transformed
An Efficient Synthesis of Nitroalkenes by Alkene Cross Metathesis: Facile Access to Small Ring Systems
作者:Graham P. Marsh、Philip J. Parsons、Clive McCarthy、Xavier G. Corniquet
DOI:10.1021/ol070557k
日期:2007.7.1
A synthesis of highly functionalized nitroalkenes is reported that utilizes a cross metathesis (CM) reaction between simple aliphatic nitrocompounds and a range of substituted alkenes. This chemistry offers a simple and attractive route to nitroalkenes that would otherwise be difficult to prepare, and that have a very useful application as precursors to a variety of heterocyclic entities.