What does OsO4 do in a reaction?

In organic synthesis OsO4 is widely used to oxidize alkenes to the vicinal diols, adding two hydroxyl groups at the same side (syn addition). See reaction and mechanism above. This reaction has been made both catalytic (Upjohn dihydroxylation) and asymmetric (Sharpless asymmetric dihydroxylation).

What forms when an alkene reacts with OsO4?

Alkene Dihydroxylation With Osmium Tetroxide (OsO4): How It Works. The reaction works through a concerted process whereby two oxygens from the osmium interact with one face of the double bond. This results in a 5-membered ring (called an osmate ester) and generates the syn stereochemistry.

What happens when ethene is treated with osmium tetroxide?

Cycloaddition of osmium tetroxide with ethene proceeds via a cyclic transition state to form an osmate ester. Addition occurs on the same side of the ethene molecule to give a syn-addition. Osmium(VIII) is reduced to Os(VI) over the reaction which is an oxidation.

How is OsO4 prepared?

Discovery and Preparation Industrially, OsO4 is made from crude platinum concentrates by oxidative acid distillation and is then separated from ruthenium tetroxide. In the laboratory it is best made by direct oxidation of osmium metal (2) or by the acid distillation with chlorate of almost any osmium compound.

Why is OsO4 toxic?

ACUTE: The acute toxicity of osmium tetroxide is high, and it is a severe irritant of the eyes and respiratory tract. Exposure to osmium tetroxide vapor can damage the cornea of the eye. Contact of the vapor with skin can cause dermatitis, and direct contact with the solid can lead to severe irritation and burns.

What type of reaction is ozonolysis?

Ozonolysis refers to the organic chemical reaction where ozone is employed to cleave the unsaturated bonds of alkenes, alkynes, and azo compounds (compounds with the functional diazenyl functional group). It is an organic redox reaction.

What is the name for OsO4?

Osmium tetroxide
Osmium tetroxide (also osmium(VIII) oxide) is the chemical compound with the formula OsO4.

Is pure Osmium toxic?

The metal is not toxic, but its oxide is volatile and very toxic, causing lung, skin and eye damage. Osmium occurs uncombined in nature and also in the mineral osmiridium (an alloy with iridium).

Is Osmium safe to handle?

Health effects of osmium Osmium tetroxide, OsO4, is highly toxic. Concentrations in air as low as 10-7 g m-3 can cause lung congestion, skin damage, and severe eye damage. The oxide, in particular, should only ever be handled by a properly qualified chemist.

What is ozonolysis give an example?

Ozonolysis: When an alkene reacts with ozone in an inert solvent (ether, CCl4etc.), an explosive and unstable ozonide is formed. For example, suppose the products of ozonolysis are ethanal and propanone.

What is Saytzeff rule give an example?

According to Saytzeff rule “In dehydrohalogenation reactions, the preferred product is that alkene which has the greater number of alkyl groups attached to the doubly bonded carbon atoms.” For example: The dehydrohalogenation of 2-bromobutane yields two products 1-butene and 2-butene.

What is the oxidation number of OsO4?

+8
In OsO4, osmium is bonded to four oxygen atoms each with a double bond. So, the oxygen has a -2 oxidation state. Hence the oxidation number of osmium is +8.