Development of a [2 + 2]-Nitroso/Alkene Cycloaddition Using Sodium Tetrakis[3,5-bis(trifluoromethyl)phenyl]borate Catalyst: Controlled Chemoselectivity of Two Equilibrating Isomeric Intermediates
作者:Jia-Xuan Chen、Prakash D. Jadhav、Ching-Nung Chen、Rai-Shung Liu
DOI:10.1021/acs.orglett.1c01987
日期:2021.8.20
Sodium tetrakis[3,5-bis(trifluoromethyl)-phenyl]borate (NaBArF) catalyzes the [2 + 2] cycloaddition of 1,4-disubstituted cyclopenta-1,3-dien-2-yl esters with nitrsobenzene in toluene, affording two isolable regioisomers of 6-oxa-7-azabicyclo[3.2.0] heptanes, which thermally rearrange into the same 4-aminocyclopent-1-en-3-ones. In the case of 4-substituted cyclopenta-1,3-dien-2-yl esters, their initial
四[3,5-双(三氟甲基)-苯基]硼酸钠 (NaBArF) 催化 1,4-二取代环戊-1,3-二烯-2-基酯与亚硝基苯在甲苯中的 [2 + 2] 环加成反应,得到6-oxa-7-azabicyclo[3.2.0] 庚烷的两种可分离区域异构体,它们通过热重排成相同的 4-aminocyclopent-1-en-3-ones。在 4-取代的环戊基-1,3-二烯-2-基酯的情况下,它们最初的 [2 + 2] 环加成中间体经历快速扩环以有效地提供六元哌啶酮衍生物。