Stevens Katelyn, Li Shik Ki, Kaufman Emily, Schull Annika, Hassebroek Katie, Stevens Joseph, Grandbois Matthew, Viste Arlen, Duffy-Matzner Jetty
Department of Chemistry and Biochemistry, Augustana University, Sioux Falls, SD 57197, USA.
Molecules. 2024 Dec 10;29(24):5816. doi: 10.3390/molecules29245816.
This study examined the chemoselectivity and diastereoselectivity of silyl nitronate alkenyn-nitroethers in Intramolecular Silyl Nitronate Cycloadditions (ISNCs) to produce isoxazole derivatives with interesting medicinal properties. These reactions resulted in the formation of either dihydrofuro[3,4-c]isoxazolines/isoxazolidines and/or alkynyl moieties attached to 2,5-dihydrofuryl carbonyls. This study also discerned the diastereoselectivities of the resulting cyclic adducts and compared them to previous findings. The reactions were also investigated with Spartan molecular modeling computations to aid in the understanding of any displayed chemo- and/or stereoselectivity. These [3+2]-cycloaddition reactions demonstrated excellent to complete chemospecificity. The cycloadditions also demonstrated remarkable diastereospecificity in that each diastereomer of the nitroethers resulted in the formation of only one of four possible diastereomeric outcomes. The stereochemistry of the major diastereomers did not agree with previously published findings.
本研究考察了硅基硝酸酯烯炔基硝基醚在分子内硅基硝酸酯环加成反应（ISNCs）中的化学选择性和非对映选择性，以制备具有有趣药用特性的异恶唑衍生物。这些反应导致形成二氢呋喃并[3,4-c]异恶唑啉/异恶唑烷和/或连接到2,5-二氢呋喃羰基上的炔基部分。本研究还识别了所得环状加合物的非对映选择性，并将其与先前的研究结果进行了比较。还利用斯巴达分子模型计算对反应进行了研究，以帮助理解所表现出的任何化学和/或立体选择性。这些[3+2]环加成反应表现出优异至完全的化学特异性。环加成反应还表现出显著的非对映特异性，即硝基醚的每个非对映异构体仅导致四种可能的非对映异构结果中的一种形成。主要非对映异构体的立体化学与先前发表的研究结果不一致。
