Enantiomerically pure isoxazolines via addition of nitrile oxides to chiral N-acryloyl toluene-2,α-sultams
作者:Wolfgang Oppolzer、Arend J. Kingma、Sasi K. Pillai
DOI:10.1016/s0040-4039(00)93489-0
日期:1991.9
New saccharine-derived, crystalline acryloylsultams undergo efficient 1,3-dipolar cycloadditions of nitrileoxides with ≥95:5 stereoface discrimination. Products or are purified by simple crystallization and cleaved with recovery of the chirophore to provide optically pure Δ2-isoxazolines .
Enantioselective syntheses of (+)-methyl nonactate and (−)-methyl 8-epi-nonactate via asymmetric cycloadditive route
作者:Byeang Hyean Kim、Ju Young Lee
DOI:10.1016/s0040-4039(00)92241-x
日期:1992.4
Enantioselective routes to (+)-methyl nonactate (2 and (−)-methyl 8-epi-nonactate (3) are described. The cornerstone of this synthetic strategy is a combination of asymmetric silylnitronate cycloaddition and asymmetric reduction, which provides the key syn-1,3-diol intermediate 4.
The preparation of optically active δ2- isoxazolines. A model for asymmetric induction in the non lewis acid catalyzed reactions of oppolzer's chiral sultam
作者:Dennis P Curran、Byeang Hyean Kim、James Daugherty、Timothy A Heffner
DOI:10.1016/0040-4039(88)85291-2
日期:1988.1
Good diastereoselectivity (ca. ) is reported in the cycloaddition reactions of Oppolzer'schiralsultam with nitrile oxides. A model is proposed which may apply to other nonLewisacid promoted reactions of this sultam.
Asymmetric silyl nitronate cycloadditions with bornane-10,2-sultam derivatives
作者:Byeang Hyean Kim、Ju Young Lee
DOI:10.1016/s0957-4166(00)80032-4
日期:——
Asymmetric silyl nitronate cycloadditions with N-acryloyl (2R)-bornane-10,2-sultam, N-acryloyl (2S)-bornane-10,2-sultam, and N-methacryloyl (2R)-bornane-10,2-sultam have been studied. The asymmetric silyl nitronate cycloaddition/elimination methodology provides a general route for the asymmetric synthesis of 2-isoxazolines.