Tetryl-Tetrylene Addition to Phenylacetylene

Area of Science:

• Organometallic chemistry
• Main group chemistry
• Reaction mechanisms

Background:

• Organotin and organolead compounds are known for their reactivity.
• Germylenes, stannylenes, and plumbylenes offer unique electronic and steric properties.
• Understanding the addition reactions of low-valent group 14 compounds is crucial for synthetic applications.

Purpose of the Study:

• To investigate the reactivity and regioselectivity of germylenes, stannylenes, and plumbylenes with phenylacetylene.
• To elucidate the reaction pathways and stereochemical outcomes of these addition reactions.
• To explore the potential for further transformations of the addition products.

Main Methods:

• Reactions were conducted at room temperature.
• Products were isolated and characterized.
• NMR spectroscopy and relativistic DFT calculations were employed for structural and electronic analysis.
• Hydride abstraction experiments were performed using a trityl salt.

Main Results:

• Phenylacetylene undergoes regioselective and stereoselective addition with germylenes, stannylenes, and plumbylenes.
• Stannylenes exhibit higher reactivity than plumbylenes.
• Kinetic and thermodynamic products were identified in the stannylplumbylene addition, with isomerization observed.
• A dimeric lead acetylide and a four-membered ring cation were isolated.

Conclusions:

• The study demonstrates the diverse reactivity of low-valent group 14 compounds in alkyne additions.
• Stereochemical control and isomerization pathways are significant in these reactions.
• Relativistic DFT calculations aid in understanding the observed NMR chemical shifts.
• The findings provide insights into the synthesis of novel organometallic compounds.