The asymmetric annulation of a range of α,β-unsaturated acyl ammonium intermediates, formed from isothiourea HBTM 2.1 and anhydrides with either 1,3-dicarbonyls, β-ketoesters or azaaryl ketones gives either functionalised esters (upon ring opening), dihydropyranones or dihydropyridones in good yields (up to 93%) and high enantioselectivity (up to 97% ee).
一系列α,β-不饱和酰胺
铵中间体的不对称环化反应,这些中间体由异
硫脲HBTM 2.1与酸酐(带有1,3-二羰基、β-
酮酯或氮杂芳基酮)反应形成,可以高产率(高达93%)和高对映选择性(高达97% ee)得到功能化的酯(环打开后)、二氢
吡喃酮或
二氢吡啶酮。