Ethynyl-SF4-Pyridines: Reagents for SF4-Alkynylation to CarbonylCompounds

Thetrans-tetrafluoro-lambda 6-sulfanyl (SF4)unitismedicinally attractive because of its high electronegativity,lipophilicity, and unique hypervalent structure. Thetrans-SF4unitcan characteristically connect two independent molecules linearly.However, there is no example of the use of this unit for medicinalchemistry due to difficulties in synthesis. We report thefirstsynthesis of (ethynyl-trans-tetrafluoro-lambda 6-sulfanyl)pyridines (t-ethynyl-SF4-pyridines) and their use as versatile reagents for thefirst direct SF4-alkynylation to carbonyl compounds. The additionreaction oft-ethynyl-SF4-pyridines to the carbonyl group in thepresence of MeLi smoothly afforded pyridine-SF4-propargylictertiary and secondary alcohols in high yields.

Automated summary

The trans-tetrafluoro-lambda 6-sulfanyl (SF4) unit is of medicinal interest due to its high electronegativity, lipophilicity, and unique hypervalent structure. Despite the difficulties in synthesis, the first synthesis of (ethynyl-trans-tetrafluoro-lambda 6-sulfanyl) pyridines and their use as versatile reagents for SF4-alkynylation to carbonyl compounds was reported. The addition reaction of t-ethynyl-SF4-pyridines to carbonyl groups in the presence of MeLi yielded pyridine-SF4-propargylic tertiary and secondary alcohols in high yields.