28104-96-3Relevant academic research and scientific papers
Enantioselective Synthesis of Cyclopropanone Equivalents and Application to the Formation of Chiral β-Lactams
Jang, Yujin,Johnson, J. Drake,Jung, Myunggi,Lindsay, Vincent N. G.,Poteat, Christopher M.,Williams, Rachel G.
supporting information, p. 18655 - 18661 (2020/08/21)
Cyclopropanone derivatives have long been considered unsustainable synthetic intermediates because of their extreme strain and kinetic instability. Reported here is the enantioselective synthesis of 1-sulfonylcyclopropanols, as stable yet powerful equivalents of the corresponding cyclopropanone derivatives, by α-hydroxylation of sulfonylcyclopropanes using a bis(silyl) peroxide as the electrophilic oxygen source. This work constitutes the first general approach to enantioenriched cyclopropanone derivatives. Both the electronic and steric nature of the sulfonyl moiety, which serves as a base-labile protecting group and confers crystallinity to these cyclopropanone precursors, were found to have a crucial impact on the rate of equilibration to the corresponding cyclopropanone. The utility of these cyclopropanone surrogates is demonstrated in a mild and stereospecific formal [3+1] cycloaddition with simple hydroxylamines, leading to the efficient formation of chiral β-lactam derivatives.
THE ASYMMETRIC SYNTHESIS OF β-LACTAMS. STEREOCONTROLLED ASYMMETRIC TANDEM MICHAEL ADDITIONS AND ALKYLATIONS OF α,β-UNSATURATED ACYL LIGANDS BOUND TO THE CHIRAL AUXILIARY 5-C5H5)Fe(CO)(PPh3)>
Davies, Stephen G.,Dordor-Hedgecock, Isabelle M.,Sutton, Kevin H.,Walker, Jonathan C.
, p. 3787 - 3790 (2007/10/02)
Michael addition of lithium benzylamide to the enantiomerically pure (S)-E-crotonyl complex of 5-C5H5)Fe(CO)(PPh3)> followed by trapping of the resultant enolate with methyl iodide or methanol occurs with high diastereoselectivity and gives after decomplexation the essentially optically pure (3R),(4S)-(-)-3,4-dimethyl- and (4S)-(-)-4-methyl-N-benzyl-β-lactams respectively.Similarly, tandem addition of lithium benzylamide and methylation of the corresponding enantiomerically pure R-(-)-acryloyl complex gave after decomplexation the essentially optically pure (3S)-(-)-3-methyl-N-benzyl-β-lactam.
