other reported carbeneadditions to these moieties, full racemization occurs when enantiopure Trögerbases are used as substrates. To pinpoint the origin of this unexpected behavior, a key elemental step of the mechanism was evaluated and tested. Interestingly, it is not only the initial ring‐opening but also the latter reversible Mannich reaction of the imino‐substituted ethano Tröger base intermediate
Diversity-oriented synthesis of heterocycles and macrocycles by controlled reactions of oxetanes with α-iminocarbenes
作者:Alejandro Guarnieri-Ibáñez、Florian Medina、Céline Besnard、Sarah L. Kidd、David R. Spring、Jérôme Lacour
DOI:10.1039/c7sc00964j
日期:——
tetrahydrofurans, 13- and 15-membered ring aza-macrocycles can be prepared selectively via formal [1 + 4], [5 + 4 + 4] and [3 + 4 + 4 + 4] condensations of α-imino carbenes and oxetanes under Rh(II)-catalysis or thermal activation. Spirocyclic N-heterocycles are also accessible by means of Buchwald–Hartwig and Pictet–Spengler cyclizations. By reaction control, substrate selection or further derivatization, a
Nickel-Catalyzed Coupling of <i>N</i>-Sulfonyl-1,2,3-triazole with <i>H</i>-Phosphine Oxides: Stereoselective and Site-Selective Synthesis of α-Aminovinylphosphoryl Derivatives
nickel-catalyzed coupling of N-sulfonyl-1,2,3-triazole with various H-phosphine oxides for the construction of C(sp2)–P bonds is established. This unexpected reaction proceeds through a formal nickel-bound ketenimine pathway, representing a previously unknown 1,2-reactivity type of an azavinyl carbene. The method provides an efficient approach to the stereoselective and site-selective synthesis of α-aminovinylphosphoryl