Sulfides by addition of thiols to alkenes

To THF (10 ml), the alkene (5 mmol), 9-BBN (0.025mmol, 0.5% equiv) in THF, and an alkanethiol (5 mmol) were added successively at 0°C and the mixture was stirred for lh at the same temperature. The dialkyl sulfides were isolated directly by simple distillation (without any work-up procedures). Yields 78-99%. 

The chemistry of crown thioethers and thioether cages is a fast-developirg field [23], and their synthesis involves a caesium carbonate ring closure [24,25]. 

A new type of approach to thiocrown ether synthesis involving a [2 + 2] coupling of o-dithiol and w-dihalide units in the presence of a boron aluminium alkoxide couple has been described [27]. 

If most of the research on crown and cage thioethers has concerned their synthesis and exploratory work on their coordination chemistry, their complexing properties and capacity to stabilize low oxidation states of transition metals should be expected to lead to new applications, as for their oxygen and nitrogen analogues. 

---