Experiment 7, page 2

This work arose from the observation by Professor Bill Griffith of this department that tertiary
amines, and bicyclic tertiary amines in particular, accelerate the rate of osmium tetroxide
dihydroxylation of olefins by co-ordination to the metal.6The ligand systems shown above are the
result of many years of experimentation by the Sharpless group and others. Note that, since natural
alkaloids are only available in one enantiomeric form, the ligands which give rise to opposite
enantiomers in the dihydroxylation are derived from two different alkaloids. The ligands are thus
not enantiomers of each other, but are termed 'pseudoenantiomeric' by Sharpless.
In this experiment, you will be using the commercial AD-mix - a powder containing an osmium
source (K2OsO2(OH)4), the chiral ligand ([DHQ]2PHAL for AD-mix α, [DHQD]2PHAL for AD-
mix β), a co-oxidant for regeneration of osmium (VIII) (K3Fe(CN)6and a pH buffer (K2CO3) - to
perform the dihydroxylation of one of several olefins.

HAZARD DATA - READ THIS BEFORE GOING ANY FURTHER!!!!

AD-MIX αor β
AD-MIXES contain approx. the following chemicals per 4.2g loading (as used here):
Potassium osmate: 4.4mg
(DHQ)2PHAL or (DHQD)2PHAL: 23mg
Potassium ferricyanide: 2.94g
Potassium carbonate: 1.24g

POTASSIUM OSMATE:
TOXIC
SEVERE IRRITANT TO EYES AND RESPIRATORY SYSTEM

Violet solid, m.pt. decomposes. Soluble in water, with slow decomposition. OES 0.002 mg/m3(Os)

Toxic effects:

Toxic by ingestion, or in contact with skin/eyes. Severe irritant to eyes and respiratory
system. If ingested can cause abdominal pain and vomiting, and irritation of the
respiratory system with coughing. Eye contact results in severe pain, blurred vision and
possible blindness.
Incompatible with strong oxidising materials.
Gives off toxic fumes in fire.
Absorb onto inert material and package in containers for disposal.

Hazardous reactions:
Fire hazards:
Spillage & disposal:

POTASSIUM FERRICYANIDE (POTASSIUM HEXACYANOFERRATE(III) ):
HARMFUL BY INGESTION

Ruby red crystals or orange powder; m.p. n/a. Very soluble in water. OEL not assigned

Toxic effects:
Hazardous reactions:

Harmful by ingestion. Irritating to skin eyes.
No known hazards, although solutions should NOT be treated with acid to avoid
generation of hydrogen cyanide.
MAY EVOLVE TOXIC FUMES IN FIRE. Flash point 76ºC, ignition temp.not
available; extinguish fire with dry powder.
Mop up with plenty of water and run to waste, diluting with copious water. For larger
spillages, transfer to container for disposal.

Fire hazards:

Spillage & disposal: