233596-91-3Relevant academic research and scientific papers
Enantioselective preparation of 3,4,5-trisubstituted 4,5-dihydroisoxazoles and their stereoselective elaboration of 5-side chain
Kamimura, Akio,Kaneko, Yukio,Ohta, Ayaki,Matsuura, Kenji,Fujimoto, Yasuo,Kakehi, Akikazu,Kanemasa, Shuji
, p. 9613 - 9620 (2007/10/03)
The magnesium ion-induced nitrile oxide cycloaddition to chiral α-silylallyl alcohols was examined. Treatment of chiral allyl alcohol with nitrile oxide in the presence of magnesium cation resulted in the smooth progress of the 1,3-dipolar cycloaddition to give optically active 4,5-dihydroisoxazoles in good yields. The present procedure serves as a good method for the preparation of multi-substituted 4,5-dihydroisoxazoles with high enantiomeric excess. When exposed to tetrabutylammonium fluoride (TBAF), the cycloadducts were converted into 4-substituted-5,6-dihydro-4H-[1,2]-oxazines in good yields without loss of optical purity. Acylsilanes, obtained by the oxidation of the cycloadduct, underwent stereoselective allylation reaction induced by Lewis acid to accomplish the elongation of C5-side chain in a stereoselective manner.
Enantioselective preparation of 3,4,5-trisubstituted-4,5- dihydroisoxazoles and 4-substituted-5,6-dihydro-4H-[1,2]-oxazines by nitrile oxide cycloaddition to α-silyl allyl alcohols
Kamimura, Akio,Kaneko, Yukio,Ohta, Ayaki,Kakehi, Akikazu,Matsuda, Haruhiko,Kanemasa, Shuji
, p. 4349 - 4352 (2007/10/03)
Regio- and stereoselective 1,3-dipolar cycloaddition of nitrile oxide to optically active α-silyl allyl alcohol provides a useful preparation of 3,4,5-trisubstituted 4,5-dihydroisoxazoles, which are readily converted into chiral 4-substituted 5,6-dihydro-4H-[1,2]-oxazines in 73-100% yields on treatment with TBAF.
