A Nonmetal Approach to α‐Heterofunctionalized Carbonyl Derivatives by Formal Reductive XH Insertion

Abstract

Keeping it organic: A direct synthesis of α-alkoxy and α-amino ester derivatives by direct reductive coupling of widely available, stable α-keto esters and protic pronucleophiles is described (see scheme; X = OR, NR(2)). The method serves as a convenient nonmetal alternative to X-H insertion by diazo decomposition.

Phosphorus(III)-Mediated Reductive Condensation of α-Keto Esters and Protic Pronucleophiles

“…2 We have shown that these Kukhtin-Ramirez adducts further react to incorporate a range of N -, O -, and C -based protic pronucleophiles with expulsion of a phosphine oxide by-product. 3,4 The process likely proceeds in stepwise fashion, initiated by proton transfer from the protic pronucleophile to the Kukhtin-Ramirez adduct, followed by Arbuzov-like displacement of the phosphine oxide leaving group. This reaction sequence therefore represents a convenient one pot process for access to a range of α–functionalized carbonyl compounds from readily available reagents and precursors.…”

“…This reaction sequence therefore represents a convenient one pot process for access to a range of α–functionalized carbonyl compounds from readily available reagents and precursors. 3,4 …”

Diazo‐ and Transition‐Metal‐Free CH Insertion: A Direct Synthesis of β‐Lactams

“…Efforts to circumvent these hazards include the use of latent diazo compounds,10b, 13 sulfur,14 or iodonium ylides15 and, more recently, cyclopropenes16 among others 17. Nevertheless, examples of CH insertion employing these surrogates remain limited,18 including for alkylidenecarbenes derived from α‐elimination of the corresponding iodonium tetrafluoroborates 18d…”

Recent Progress in the Cyclization Reactions Using Carbon Dioxide

“…[46] , 72 优先与 73 进行质子转移生成中间体 74, 随 后氨基甲酸根亲核进攻释放出膦氧化合物的同时得到 氨基甲酸酯化合物 75, 其在碱催化下闭环最终得到噁 唑啉二酮产物(Scheme 16). 由于 Kukhtin-Ramirez 加合 物 72 的高亲核反应活性 [47] , 此羧化反应只需在 101 kPa 的二氧化碳气氛下就可顺利进行.…”