Unexpected Zwitterionic Allenyls from Silylenes and a Fischer Alkynylcarbene: A Remarkable Silylene‐Promoted Rearrangement

Cabeza, Javier A.; García‐Álvarez, Pablo; Gallego, Manuel Requena; González‐Álvarez, Laura; Merinero, Alba D.; Sierra, Miguel Á.

doi:10.1002/chem.201806275

Cited by 7 publications

(13 citation statements)

References 92 publications

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“…Only two complexes with a structure analogous to that of 4

_{boldE - boldR^{1} - boldR^{2}}

have been previously reported . They were isolated from reactions of the tungsten complex [W{C(OEt)C 2 Ph}(CO) 5 ] with the silylenes 1 Si‐Tmsm and 1 Si‐Mes (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

“…They were isolated from reactions of the tungsten complex [W{C(OEt)C 2 Ph}(CO) 5 ] with the silylenes 1 Si‐Tmsm and 1 Si‐Mes (Scheme ). Although the insertion of metal atoms into E−N bonds of amidinato‐ and guanidinatotetrylenes has been observed in several occasions, the related insertion of carbenes and other fragments is very rare.…”

Section: Resultsmentioning

confidence: 99%

“…We now report a reactivity study that involves reactions at various temperatures of two amidinatosilylenes and three amidinatogermylenes with two chromium Fischer alkynyl(ethoxy)carbene complexes. This thorough study, together with the tungsten results shown in Scheme , provides an ample panorama of the reactivity of amidinato‐HTs with Group 6 metal Fischer alkynyl(ethoxy)carbene complexes, showing that the reactions may follow three different pathways (attack of the HT to the C α , C γ , or M atoms of the metal complex), the outcome of a particular reaction depending upon the reaction temperature, the Group 6 metal atom (Cr or W), the tetrel atom (Si or Ge), and the volumes of both the amidinato‐HT and the alkynyl terminal group.…”

Section: Introductionmentioning

confidence: 90%

“…In addition, from reactions of the amidinatosilylenes Si( t Bu 2 bzm)R 1 (R 1 =mesityl (2,4,6‐(CH 3 ) 3 C 6 H 2 , Mes), CH 2 SiMe 3 (Tmsm)) with [W{C(OEt)C 2 Ph}(CO) 5 ], we succeeded in synthesizing unprecedented zwitterionic metal–allenyl complexes in which the original carbene C α atom forms part of both the allene fragment and of a Si‐C‐N‐C‐N five‐membered ring (Scheme ) …”

Section: Introductionmentioning

confidence: 99%

“… Previously reported reactivity of amidinatosilylenes with a tungsten Fischer alkynyl(ethoxy)carbene complex …”

Section: Introductionmentioning

confidence: 99%

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Two Types of σ‐Allenyl Complexes from Reactions of Silylenes and Germylenes with Chromium Fischer Alkynyl(alkoxy)carbenes

Cabeza

García‐Álvarez

Gallego

et al. 2019

Chemistry A European J

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The reactivity of amidinatotetrylenes of the type E(tBu2bzm)R1 (E=Si, Ge; tBu2bzm=N,N′‐bis(tertbutyl)benzamidinate; R1=alkyl or aryl) with the chromium Fischer alkynylcarbene complexes [Cr{C(OEt)C2R2}(CO)5] (R2=Ph; ferrocenyl, Fc) has been studied. At room temperature, two different reaction pathways have been identified: (a) attack of the amidinatotetrylene to the alkynyl C2 atom (γ‐attack), which leads to σ‐allenyl complexes in which the original Ccarbene atom maintains its attachment to the Cr(CO)5 and OEt groups (compounds 3boldE-boldR1-boldR2 ), and (b) attack of the amidinatotetrylene to the Ccarbene atom (α‐attack), which ends in σ‐allenyl complexes in which the original Ccarbene atom is not attached to the metal atom and has been inserted into an E−N bond of the amidinatotetrylene forming an E‐C‐N‐C‐N five‐membered ring (compounds 4boldE-boldR1-boldR2 ). It has been found that compounds 3boldE-boldR1-boldR2 are thermodynamically less stable than their corresponding 4boldE-boldR1-boldR2 isomers and that some of the former (E=Ge; R1=CH2SiMe3) can be transformed into the latter upon heating. At high temperatures (>70 °C) the reactions involving bulky amidinatotetrylenes (R1=Mes, tBu) end in the carbene‐substitution products [Cr{E(tBu2bzm)R1}(CO)5].

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“…Only two complexes with a structure analogous to that of 4

_{boldE - boldR^{1} - boldR^{2}}

have been previously reported . They were isolated from reactions of the tungsten complex [W{C(OEt)C 2 Ph}(CO) 5 ] with the silylenes 1 Si‐Tmsm and 1 Si‐Mes (Scheme ).…”

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

“… Previously reported reactivity of amidinatosilylenes with a tungsten Fischer alkynyl(ethoxy)carbene complex …”

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Two Types of σ‐Allenyl Complexes from Reactions of Silylenes and Germylenes with Chromium Fischer Alkynyl(alkoxy)carbenes

Cabeza

García‐Álvarez

Gallego

et al. 2019

Chemistry A European J

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The Transition Metal Chemistry of PGeP and PSnP Pincer Heavier Tetrylenes

2020

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This review article collects and discusses the syntheses of the currently known metal‐free heavier tetrylenes having a PEP pincer topology (E = tetrel atom) as well as their transition metal derivative chemistry. To date, only five PGeP germylenes and two PSnP stannylenes have been isolated. These compounds have been successfully synthesized by treating GeCl2(diox) (diox = 1,4‐dioxane), GeCl2(NHC) (NHC = N‐heterocyclic carbene) or SnCl2 with two equivalents of an appropriate lithiated phosphine. Their transition metal chemistry is dominated by processes in which, in addition to the coordination of one or both phosphane groups, the E atom ends inserted into M–M or M–X (X = anionic group) bonds. Only in a few occasions a simple coordination of the tetrylene fragment (as a neutral two‐electron‐donor ligand) has been observed. The structural and bonding characteristics of the metal‐free PEP tetrylenes and of relevant examples of their transition metal derivatives are also surveyed.

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Cyclometallation of Heavier Tetrylenes: Reported Complexes and Applications in Catalysis

Cabeza

García‐Álvarez

2021

Eur J Inorg Chem

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Heavier tetrylenes (HTs), which are the heavier analogues of carbenes, have been used as ligands in transition metal chemistry for more than 50 years. Having in mind that cyclometallation is a valuable tool to modify ligand scaffolds, with important implications in inorganic and organic chemistry, this microreview discusses in detail the reactions that have afforded complexes with cyclometallated HTs. To date, eight HT ligands, covering only silylenes and germylenes, have been reported to undergo cyclometallation, all of them on late transition metals. Structural and spectroscopic data of the isolated complexes as well as mechanistic information related to the cyclometallation processes are collected and discussed. Additionally, this minireview also surveys the catalytic applications found so far for cyclometallated HT complexes.

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Unexpected Zwitterionic Allenyls from Silylenes and a Fischer Alkynylcarbene: A Remarkable Silylene‐Promoted Rearrangement

Cited by 7 publications

References 92 publications

Two Types of σ‐Allenyl Complexes from Reactions of Silylenes and Germylenes with Chromium Fischer Alkynyl(alkoxy)carbenes

Two Types of σ‐Allenyl Complexes from Reactions of Silylenes and Germylenes with Chromium Fischer Alkynyl(alkoxy)carbenes

The Transition Metal Chemistry of PGeP and PSnP Pincer Heavier Tetrylenes

Cyclometallation of Heavier Tetrylenes: Reported Complexes and Applications in Catalysis

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