Pyrrolidines from β-Aminoselenides via Radical Cyclization. Diastereoselectivity Control by the N-Substituent
作者:Magnus Besev、Lars Engman
DOI:10.1021/ol005829x
日期:2000.6.1
radicals-were prepared by ring opening of N-allylaziridines with benzeneselenol under acidic conditions or by sodium cyanoborohydride reduction of N-allylimines of alpha-phenylselenenyl ketones. The effect of various N-protective groups (acyl, sulfonyl, or phosphinoyl) on diastereoselectivity in thermally or photochemically initiated 3-aza-5-hexenyl reductive radical cyclization was studied. Whereas N-unprotected
N-烯丙基-β-氨基烷基苯基硒化物-3-氮杂-5-己烯基的前体-通过在酸性条件下将N-烯丙基z啶与苯硒酚开环或通过氰基硼氢化钠还原α-苯基硒烯基酮的N-烯丙氨酸来制备。研究了各种N-保护基(酰基,磺酰基或膦酰基)对热或光化学引发的3-氮杂-5-己烯基还原性自由基环化中非对映选择性的影响。N-未保护的衍生物可提供具有良好选择性的反式2,4-二取代吡咯烷,而二苯基膦酰基则可高度顺式选择性地引导环化反应。