Abstract：
N,O-acetals are found as structural motifs in natural products and are important synthetic precursors for N-acylimines as building blocks in organic synthesis for C-C-bond formation and amines. For the synthesis of N,O-acetals, an acid-, base- and metal-free catalytic method is reported applying N,N-di-(2,6-diisopropyl)-1,7-dicyano-perylen-3,4,9,10-tetracarboxylic acid imide and N,N-di-(2,6-diisopropyl)-1,6,7,12-tetrabromo-2,5,8,11-tetracyano-perylen-3,4,9,10-tetracarboxylic acid imide as extremely electron-deficient photocatalysts. The first perylene bisimide highly selectively photocatalyzes the formation of the N,O-acetals as products in high yields, and the second and more electron-deficient perylene bisimide allows these reactions without thiophenol as an H-atom transfer reagent. Calculated electron density maps support this. The reaction scope comprises different substituents at the nitrogen of the enamides and different alcohols as starting material. Dehydroalanines are converted to non-natural amino acids which shows the usefulness of this method for organic and medicinal chemistry.
摘要：
N,O-缩醛在天然产物中被发现是结构基序，并且是N-acyliames的重要合成前体，是有机合成中C-C键形成和胺的组成部分。对于N的合成，O-缩醛,一种酸-，据报道，无碱和无金属催化方法应用N，N-二-(2,6-二异丙基)-1,7-二氰基-哌啶-3,4,9,10-四羧酸酰亚胺和N,N-二-（2,6-二异丙基）-1,6,7,12-四溴-2,5,8,11-四氰基-哌啶-3,4,9,10-四羧酸酰亚胺作为极度缺电子的光催化剂。第一种二酰亚胺高度选择性地光催化形成N，O-缩醛作为高收率的产品，第二个和更缺电子的二亚二酰亚胺可以在没有苯硫酚作为H原子转移试剂的情况下进行这些反应。计算的电子密度图支持这一点。反应范围包括在烯酰胺的氮上的不同取代基和作为起始材料的不同醇。脱氢丙氨酸被转化为非天然氨基酸，这表明该方法对有机和药物化学的有用性。
