Lakhasly

This reactivity of heterocyclic α-C−H positions with organolanthanides raises the intriguing question of whether similar processes might be employed to activate other heterocyclic 2-position functionalities such as organometalloids.

For example, trialkyltin groups might be catalytically transferred from the heterocyclic 2-position to generate valuable new organotin compounds.

If α-C−SnR3 activation using 2(trimethylstannyl)pyridine (1) as the substrate proceeded similarly, subsequent insertive chemistry at Cp2La(2-pyridyl) (3) would then produce Cp2La(2-(2-pyridyl)ethyl) complexes.

Subsequent α-C−SnR3/C−La σ-bond metathesis by a new molecule of 1 would then regenerate 3 and produce 2-[2(trimethylstannyl)ethyl]pyridine (4).

In this study we explore the novel activation of 2-(Me3Sn)arenes as an approach to accessing a variety of novel organotin species.

It will be seen that ethylene undergoes insertion into the La−C bond of the Cp*2La(2-pyridyl) (3) intermediate at 25 °C, followed by carbostannolysis, to catalytically generate 2-(2(trimethylstannyl)ethyl)pyridine (4).

Furthermore, the organolanthanide alkyl Cp2LaCH(TMS)2 (2a) and organolanthanide hydride (Cp2LaH)2 (2b) both initiate the conversion of 2(trimethylstannyl)pyridine (1) with 1-hexyne to yield (E)-2butyl-1-(trimethylstannyl)-oct-1-en-3-yne ((E)-9).

This transformation appears to be general for α-monosubstituted and αdisubstituted terminal alkynes.

This reactivity of heterocyclic α-C−H positions with organolanthanides raises the intriguing question of whether similar processes might be employed to activate other heterocyclic 2-position functionalities such as organometalloids.

For example, trialkyltin groups might be catalytically transferred from the heterocyclic 2-position to generate valuable new organotin compounds.

If α-C−SnR3 activation using 2(trimethylstannyl)pyridine (1) as the substrate proceeded similarly, subsequent insertive chemistry at Cp2La(2-pyridyl) (3) would then produce Cp2La(2-(2-pyridyl)ethyl) complexes.

Subsequent α-C−SnR3/C−La σ-bond metathesis by a new molecule of 1 would then regenerate 3 and produce 2-[2(trimethylstannyl)ethyl]pyridine (4).

In this study we explore the novel activation of 2-(Me3Sn)arenes as an approach to accessing a variety of novel organotin species.

It will be seen that ethylene undergoes insertion into the La−C bond of the Cp*2La(2-pyridyl) (3) intermediate at 25 °C, followed by carbostannolysis, to catalytically generate 2-(2(trimethylstannyl)ethyl)pyridine (4).

Furthermore, the organolanthanide alkyl Cp2LaCH(TMS)2 (2a) and organolanthanide hydride (Cp2LaH)2 (2b) both initiate the conversion of 2(trimethylstannyl)pyridine (1) with 1-hexyne to yield (E)-2butyl-1-(trimethylstannyl)-oct-1-en-3-yne ((E)-9).

This transformation appears to be general for α-monosubstituted and αdisubstituted terminal alkynes.