H. Heydt

Bio: H. Heydt is an academic researcher from Kaiserslautern University of Technology. The author has contributed to research in topics: Phosphorus & Diazo. The author has an hindex of 5, co-authored 41 publications receiving 714 citations.

The Fascinating Chemistry of 1,3,5-Triphosphinines and Valence Isomers [1]

Abstract: In contrast to their all-carbon analogues, phosphaalkyne cyclooligomers only became accessible a few years ago. A milestone in the chemistry of the cyclotrimers was the synthesis and structural characterization of the 1,3,5-triphosphinines 11, obtained by the trimerization of phosphaalkynes in the presence of a vanadium catalyst. This review is focused on the reactivity of these new phosphorus heterocycles.

p‐Toluenesulfonyl Azide

Abstract: [941-55-9] C7H7N3O2S (MW 197.24) InChI = 1S/C7H7N3O2S/c1-6-2-4-7(5-3-6)13(11,12)10-9-8/h2-5H,1H3 InChIKey = NDLIRBZKZSDGSO-UHFFFAOYSA-N (introduction of azide and diazo groups into organic compounds;2 serves as a source of nitrene and 1,3-azide dipoles for [3 + 2] cycloadditions;3 used for the synthesis of N-tosylphosphinimines,4 -sulfimines, and -sulfoximines5) Alternate Names: tosyl azide. Physical Data: mp 21–22 °C; bp 110–115 °C/0.001 mmHg;6 d25 1.286 g cm−3; 1.55010. Solubility: sol chloroform, diethyl ether, acetone. Form Supplied in: oily colorless liquid. Analysis of Reagent Purity: IR (neat) ν = 2130 (strong, NNN), 1380 and 1180 (strong, SO2) cm−1; 1H NMR (CDCl3) δ = 2.47 (s, CH3), 7.40 (d, J = 8 Hz, m-SO2C6H4), 7.84 (d, J = 8 Hz, o-SO2C6H4).7 Preparative Methods: the simplest synthetic method for tosyl azide is the reaction of p-Toluenesulfonyl Chloride with Sodium Azide. Tosyl azide prepared in ethanol may contain 7–20% of ethyl p-toluenesulfonate;8 the formation of this byproduct can be avoided by working in aqueous acetone instead of ethanol.9, 10 The 1H NMR spectrum of tosyl azide prepared (99% yield) according to Curphey exhibits signals for traces of dichloromethane ( 1.5%) of an impurity. Polymer-bound tosyl chloride can be transformed to polymer-bound tosyl azide.11 A polymer-bound phase-transfer catalyst may also be employed (94% yield).12 Further methods for the preparation of tosyl azide are the oxidation of p-Toluenesulfonylhydrazide by Iron(III) Nitrate–K10 Montmorillonite Clay (83% yield),13 by Nitrogen Dioxide in CCl4 (95% yield),14 or by Nitrosonium Tetrafluoroborate (85% yield).15 Handling, Storage, and Precautions: crystallizes to a white solid at −20 °C and can be stored indefinitely at this temperature. Particular care is required for all reactions in which tosyl azide is heated at or above 100 °C. The initial temperature of the explosive decomposition is about 120 °C.16 Severe explosions during the attempted distillation of tosyl azide have been reported.6, 17 Polymer-bound tosyl azide can be stored indefinitely at room temperature and, in contrast to tosyl azide itself, is not sensitive to mechanical shock. Use in a fume hood.

Electrochemical strategies for C-H functionalization and C-N bond formation.

Abstract: Conventional methods for carrying out carbon–hydrogen functionalization and carbon–nitrogen bond formation are typically conducted at elevated temperatures, and rely on expensive catalysts as well as the use of stoichiometric, and perhaps toxic, oxidants. In this regard, electrochemical synthesis has recently been recognized as a sustainable and scalable strategy for the construction of challenging carbon–carbon and carbon–heteroatom bonds. Here, electrosynthesis has proven to be an environmentally benign, highly effective and versatile platform for achieving a wide range of nonclassical bond disconnections via generation of radical intermediates under mild reaction conditions. This review provides an overview on the use of anodic electrochemical methods for expediting the development of carbon–hydrogen functionalization and carbon–nitrogen bond formation strategies. Emphasis is placed on methodology development and mechanistic insight and aims to provide inspiration for future synthetic applications in the field of electrosynthesis.

Efficient and selective N-alkylation of amines with alcohols catalysed by manganese pincer complexes.

Abstract: Borrowing hydrogen (or hydrogen autotransfer) reactions represent straightforward and sustainable C-N bond-forming processes. In general, precious metal-based catalysts are employed for this effective transformation. In recent years, the use of earth abundant and cheap non-noble metal catalysts for this process attracted considerable attention in the scientific community. Here we show that the selective N-alkylation of amines with alcohols can be catalysed by defined PNP manganese pincer complexes. A variety of substituted anilines are monoalkylated with different (hetero)aromatic and aliphatic alcohols even in the presence of other sensitive reducible functional groups. As a special highlight, we report the chemoselective monomethylation of primary amines using methanol under mild conditions.

Copper Hydride Catalyzed Hydroamination of Alkenes and Alkynes

Abstract: Over the past few years, CuH-catalyzed hydroamination has been discovered and developed as a robust and conceptually novel approach for the synthesis of enantioenriched secondary and tertiary amines. The success in this area of research was made possible through the large body of precedent in copper(I) hydride catalysis and the well-explored use of hydroxylamine esters as electrophilic amine sources in related copper-catalyzed processes. This Minireview details the background, advances, and mechanistic investigations in CuH-catalyzed hydroamination.

New Strategies for the Transition-Metal Catalyzed Synthesis of Aliphatic Amines.

Abstract: Transition-metal catalyzed reactions that are able to construct complex aliphatic amines from simple, readily available feedstocks have become a cornerstone of modern synthetic organic chemistry. I...

Homogeneous Catalysis by Cobalt and Manganese Pincer Complexes

Abstract: Homogeneous catalysis of organic transformations by metal complexes has been mostly based on complexes of noble metals. In recent years, tremendous progress has been made in the field of base-metal catalysis, mostly with pincer-type complexes, such as iron, cobalt, nickel, and manganese pincer systems. Particularly impressive is the explosive growth in the catalysis by Mn-based pincer complexes, the first such complexes being reported as recently as 2016. This review covers recent progress in the field of homogeneously catalyzed reactions using pincer-type complexes of cobalt and manganese. Various reactions are described, including acceptorless dehydrogenation, hydrogenation, dehydrogenative coupling, hydrogen borrowing, hydrogen transfer, H–X additions, C–C coupling, alkene polymerization and N2 fixation, including their scope and brief mechanistic comments.