Organotin Compounds

Robert Ono4 December 2012

Organotin Uses

Sn

R

R

R

H

Br

Sn

R

R

R

Br

H

AIBN

Sn

R

R

R

Cl

1) n-BuLi

2) Ar-Br Ar-SnR3

Ar-SnR3 + Ar2-Xcat.

Ar-Ar2

• Protodehalogenation

• Cross-Coupling (Stille)

Trialkyltin Chlorides

Size of R

Reactivitydecrease increase

Toxicity

Example:SnMe3Cl vs. SnBu3Cl

LD50 12.6 mg/kg 129 mg/kg (NaCN LD50: 4.8 mg/kg)

Toxicity• Ingestion, inhalation, or skin exposure • Skin, eye irritation• Neurotoxin

– Accumulates in parts of the brain– Dizzyness, vertigo, memory loss, aggressiveness…

• Reproductive toxicity in lab animals• Not really carcinogenic• Also,

Sn

n-Bu

n-Bu

n-Bu

H H2O Sn

n-Bu

n-Bu

n-Bu

OH H2

Sn

n-Bu

n-Bu

n-Bu

Cl H2O Sn

n-Bu

n-Bu

n-Bu

OH HCl

Handling

• Proper PPE – Protect eyes, hands, skin

• Chlorides – avoid contact with moisture• Hydrides – handle under inert gas atmosphere• Disposal:

– Wash contaminated equipment with organic solvent, into container, tag for pickup

– Same for small spills (larger spills, call EHS)

How to get rid of R3Sn-X byproducts from your reactions

Sn

R

R

R

Cl

1) n-BuLi

2) Ar-Br Ar-SnR3 ( + SnR3-Br or Cl)

• Vigorously stir crude reaction mixture (in organic solvent) with 1M NaOH for 1h

• Separate organic phase, filter through silica

• R3Sn-X is converted to polar R3Sn-OH, which does not elute on silica gel

Tetrahedron Lett. 1998 , 39 , 2123.