Publication detail

Beyond simple hetero Diels-Alder cycloadditions. A new type of element-ligand cooperativity at N, C,N-coordinated arsinidene and stibinidene centres in the reaction with an electron-deficient alkyne

Year: 2022

Type of publication: článek v odborném periodiku

Name of source: Dalton Transactions

Publisher name: Royal Society of Chemistry

Place: Cambridge

Page from-to: 15933-15945

Titles:

Language	Name	Abstract	Keywords
cze	Za jednoduchými hetero Diels-Alderovými cycloadicemi. Nový typ spolupráce kov-ligandu v N, C,N-koordinovaných arsinidenech a stibinidenech	Reactivita organopniktogenů(I) [2,6-(DippN=CH)(2)C6H3]E (1-E, where E = As, Sb, Bi; Dipp = 2,6-iPrC(6)H(3)) a [2-(DippN=CH)-6-(DippHCH(2))C6H3]E (6-E, E = As a Sb), ke elektronově deficitním alkynům byla studována.	alkyn; Diels-Alderová cykloadice; komplexy; organopniktogen; katalýza; arsinideny; stibinideny
eng	Beyond simple hetero Diels-Alder cycloadditions. A new type of element-ligand cooperativity at N, C,N-coordinated arsinidene and stibinidene centres in the reaction with an electron-deficient alkyne	The reactivity of two types of organopnictogen(I) N,C,N-pincer ligand coordinated compound, i.e. [2,6-(DippN=CH)(2)C6H3]E (1-E, where E = As, Sb, Bi; Dipp = 2,6-iPrC(6)H(3)) and [2-(DippN=CH)-6-(DippNHCH(2))C6H3]E (6-E, where E = As or Sb), toward an electron-deficient alkyne, i.e. dimethyl acetylenedicarboxylate (DMAD), is reported. All reactions represent remarkable examples of element-ligand cooperation (ELC). In the first step, all compounds react via dearomatization of a latent heteropnictole ring producing rare examples of hetero Diels-Alder (DA) adducts. These compounds then smoothly convert to 1-arsanaphthalenes via hydrogen migration, thereby recovering the aromatic 10 pi-electron system. Furthermore, in the case of bis(imino) derivatives of 1-E, heating of DA adducts in pyridine led to a hydrogenation of the triple bond of DMAD with the concomitant recovery of the univalent pnictinidene centre, which is in turn able to activate the second molecule of DMAD. In contrast, the non-symmetric derivative of 6-As upon heating in pyridine produced bicyclic trivalent arsenic compounds as a result of an attack of the pendant secondary NH group into the arsa-heterocyclic system. For 6-Sb, a remarkable stoichiometric hydrogenation of the DMAD molecule was observed by NMR spectroscopy involving the reductive elimination of dimethylfumarate in the final step of the reaction sequence. The whole study is accompanied by a theoretical survey that describes the main thermodynamic parameters of the reported reactions and explains the reaction pathways observed in the experiments.	bond covalent radii; oxidative addition; activation; complexes; catalysis; dehydrogenation; pnictinidenes; metathesis; reduction; alcohols

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