120329-63-7Relevant academic research and scientific papers
Asymmetric 1,3-dipolar cycloadditions to 5-(R)-menthyloxy-2(5H)-furanone
Rispens,Keller,De Lange,Zijlstra,Feringa
, p. 607 - 624 (2007/10/02)
Various diazo compounds, nitrile oxides, nitrones and azomethine ylides were examined in 1,3-dipolar cycloadditions to enantiomerically pure 5-(R)-menthyloxy-2(5H)-furanone 1a. Pyrazoline 9 was obtained in 100% c.y. as a mixture of 2 diastereoisomers in ratios up to 72:28, whereas pyrazoline 16 was obtained in 100% c.y. as a single enantiomer. Photochemically pyrazolines 9 and 10 have been converted to cyclopropanes 11 and 13. Under thermal conditions pyrazoline 9 is converted to 4-methyl-5-menthyloxy-2(5H)-furanone. Isoxazoles 21a-24a were obtained enantiomerically pure via nitrile oxide addition to 1a in 64-67% yield. Nitrone addition afforded isoxazolidines 27, 28 and 34 with complete anti-facial- and regiochemistry, but with endo-exo-selectivities up to 76%. Enantiomerically pure isoxazolidines were obtained in 25-75% yield. Pyrrolidine 36 was obtained diastereomerically pure in 81% c.y. Pyrrolidines 42 and 45, however, were obtained as diastereomeric mixtures in 37% resp. 6% yield.
ASYMMETRIC 1,3-DIPOLAR CYCLOADDITIONS TO 5-MENTHYLOXY-2(5H)-FURANONES.
Lange, Ben de,Feringa, Ben L.
, p. 5317 - 5320 (2007/10/02)
Cycloadditions of various 1,3-dipolar reagents to chiral butenolides 1 and 5 proceed with diastereomeric excess of 20-100percent.
