Synthesis of Calcium and Ytterbium Complexes Supported by a Tridentate Imino-Amidinate Ligand and Their Application in the Intermolecular Hydrophosphination of Alkenes and Alkynes

Well-defined calcium and ytterbium complexes [{2-NC­(Ph)­NArC₆H₄CHNAr}­M­{N­(SiMe₃)₂}­(THF)] (M = Ca, Yb; Ar = 2,6-<i>i</i>Pr₂C₆H₃) have been synthesized and characterized. They catalyze the intermolecular hydrophosphination of alkenes, dienes, and alkynes with high activity and selectivity under mild conditions. Highly selective 1,4-additions (94–100%) for the conjugated dienes examined have been observed with both catalysts. The calcium complex exclusively catalyzes anti addition to alkynes, including terminal alkynes, while the ytterbium, in most cases, catalyzes syn addition. The calcium catalyst could promote hydrophosphination of hindered alkenes such as stilbene under relatively mild conditions

Cyclopropanation and Isomerization Reactions of β-Diketiminato Boron Complexes

The reaction of HC­[(CBut)­(NAr)]2Li with BCl3 yielded the azaallyl boron dichloride [ArNC­(But)­C­(H)­C­(But)­N­(Ar)]­BCl2 (1), which can be converted to the β-diketiminato boron dichloride HC­[(CBut)­(NAr)]2BCl2 (2) upon heating at 40 °C. Reaction of 1 with the bulky lithium salts LiN­(SiMe3)2 and MesLi (Mes = 2,4,6-Me3C6H2) resulted in the cyclopropanation of the CBut group via the deprotonation of the methyl group, while reactions with PhLi and LiNEt2 gave substitution products

Cyclopropanation and Isomerization Reactions of β-Diketiminato Boron Complexes

The reaction of HC­[(CBu^<i>t</i>)­(NAr)]₂Li with BCl₃ yielded the azaallyl boron dichloride [ArNC­(Bu^<i>t</i>)­C­(H)­C­(Bu^<i>t</i>)­N­(Ar)]­BCl₂ (<b>1</b>), which can be converted to the β-diketiminato boron dichloride HC­[(CBu^<i>t</i>)­(NAr)]₂BCl₂ (<b>2</b>) upon heating at 40 °C. Reaction of <b>1</b> with the bulky lithium salts LiN­(SiMe₃)₂ and MesLi (Mes = 2,4,6-Me₃C₆H₂) resulted in the cyclopropanation of the CBu^<i>t</i> group via the deprotonation of the methyl group, while reactions with PhLi and LiNEt₂ gave substitution products

Cyclopropanation and Isomerization Reactions of β-Diketiminato Boron Complexes

The reaction of HC­[(CBu^<i>t</i>)­(NAr)]₂Li with BCl₃ yielded the azaallyl boron dichloride [ArNC­(Bu^<i>t</i>)­C­(H)­C­(Bu^<i>t</i>)­N­(Ar)]­BCl₂ (<b>1</b>), which can be converted to the β-diketiminato boron dichloride HC­[(CBu^<i>t</i>)­(NAr)]₂BCl₂ (<b>2</b>) upon heating at 40 °C. Reaction of <b>1</b> with the bulky lithium salts LiN­(SiMe₃)₂ and MesLi (Mes = 2,4,6-Me₃C₆H₂) resulted in the cyclopropanation of the CBu^<i>t</i> group via the deprotonation of the methyl group, while reactions with PhLi and LiNEt₂ gave substitution products

Cyclopropanation and Isomerization Reactions of β-Diketiminato Boron Complexes

The reaction of HC­[(CBu^<i>t</i>)­(NAr)]₂Li with BCl₃ yielded the azaallyl boron dichloride [ArNC­(Bu^<i>t</i>)­C­(H)­C­(Bu^<i>t</i>)­N­(Ar)]­BCl₂ (<b>1</b>), which can be converted to the β-diketiminato boron dichloride HC­[(CBu^<i>t</i>)­(NAr)]₂BCl₂ (<b>2</b>) upon heating at 40 °C. Reaction of <b>1</b> with the bulky lithium salts LiN­(SiMe₃)₂ and MesLi (Mes = 2,4,6-Me₃C₆H₂) resulted in the cyclopropanation of the CBu^<i>t</i> group via the deprotonation of the methyl group, while reactions with PhLi and LiNEt₂ gave substitution products

Cyclopropanation and Isomerization Reactions of β-Diketiminato Boron Complexes

The reaction of HC­[(CBu^<i>t</i>)­(NAr)]₂Li with BCl₃ yielded the azaallyl boron dichloride [ArNC­(Bu^<i>t</i>)­C­(H)­C­(Bu^<i>t</i>)­N­(Ar)]­BCl₂ (<b>1</b>), which can be converted to the β-diketiminato boron dichloride HC­[(CBu^<i>t</i>)­(NAr)]₂BCl₂ (<b>2</b>) upon heating at 40 °C. Reaction of <b>1</b> with the bulky lithium salts LiN­(SiMe₃)₂ and MesLi (Mes = 2,4,6-Me₃C₆H₂) resulted in the cyclopropanation of the CBu^<i>t</i> group via the deprotonation of the methyl group, while reactions with PhLi and LiNEt₂ gave substitution products

Access to BS and BSe Double Bonds via Sulfur and Selenium Insertion into a B−H Bond and Hydrogen Migration

Stable compounds with a boron−chalcogen (S or Se) valence double bond have been prepared via sequences involving insertion of the chalcogen into a B−H bond and subsequent hydrogen migration. X-ray diffraction studies and density functional theory calculations on the resulting compounds provide convincing evidence for the boron−chalcogen multiple bonding

Base-Stabilized 1-Silacyclopenta-2,4-dienylidenes

Two novel carbene-stabilized silacyclopentadienylidenes have been obtained via dehydrohalogenation of the corresponding hydrochlorosilole with N-heterocyclic carbenes in THF at low temperature. The base-stabilized cyclic carbon substituted silylenes are highly nucleophilic, as exemplified by the nucleophilic attack on phenylacetylene to give a luminescent 1-alkenyl-1-alkynylsilole with the liberation of the coordinated carbene

Access to BS and BSe Double Bonds via Sulfur and Selenium Insertion into a B−H Bond and Hydrogen Migration

Stable compounds with a boron−chalcogen (S or Se) valence double bond have been prepared via sequences involving insertion of the chalcogen into a B−H bond and subsequent hydrogen migration. X-ray diffraction studies and density functional theory calculations on the resulting compounds provide convincing evidence for the boron−chalcogen multiple bonding

Access to BS and BSe Double Bonds via Sulfur and Selenium Insertion into a B−H Bond and Hydrogen Migration

Stable compounds with a boron−chalcogen (S or Se) valence double bond have been prepared via sequences involving insertion of the chalcogen into a B−H bond and subsequent hydrogen migration. X-ray diffraction studies and density functional theory calculations on the resulting compounds provide convincing evidence for the boron−chalcogen multiple bonding