An Unexpected Reversal of Diastereoselectivity in the [4+3]-Cycloaddition Reaction of Nitrogen-Stabilized Oxyallyl Cations with Methyl 2-Furoate
作者:Richard Hsung、Jennifer Antoline
DOI:10.1055/s-2008-1042765
日期:——
An unexpected reversal of diastereoselectivity in the [4+3] cycloaddition of methyl 2-fuorate with nitrogen-stabilized oxyallyl cations derived from epoxidation of chiral allenamides is described here. This intriguing reversal in favor of the endo-II cycloaddition pathway is likely a result of minimizing the dipole interaction between the oxyallyl cation and ester carbonyl of methyl 2-fuorate.
这里描述了在 2-氟酸甲酯与氮稳定的氧烯丙基阳离子的 [4+3] 环加成反应中非对映选择性的意外逆转,该阳离子源自手性烯丙酰胺的环氧化。这种有利于内-II 环加成途径的有趣逆转可能是最小化氧烯丙基阳离子与 2-氟甲酸甲酯的酯羰基之间偶极相互作用的结果。