Benzyl chloroformate

Benzyl chloroformate

Names
Preferred IUPAC name Benzyl carbonochloridate
Other names Benzyl chloroformate Benzyloxycarbonyl chloride Z-Chloride
Identifiers
CAS Number	501-53-1 Y
3D model (Jmol)	Interactive image
ChemSpider	9958 Y
ECHA InfoCard	100.007.205
PubChem CID	10387
InChI InChI=1S/C8H7ClO2/c9-8(10)11-6-7-4-2-1-3-5-7/h1-5H,6H2 Y Key: HSDAJNMJOMSNEV-UHFFFAOYSA-N Y InChI=1/C8H7ClO2/c9-8(10)11-6-7-4-2-1-3-5-7/h1-5H,6H2 Key: HSDAJNMJOMSNEV-UHFFFAOYAW
SMILES ClC(=O)OCc1ccccc1
Properties
Chemical formula	C8H7ClO2
Molar mass	170.59 g·mol−1
Density	1.195 g/cm3
Boiling point	103 °C (217 °F; 376 K) (20 Torr)
Hazards
Safety data sheet	External MSDS
EU classification (DSD)	C N Xn
R-phrases	R34, R50/53
S-phrases	(S1/2), S26, S45, S60, S61
Flash point	80 °C (176 °F; 353 K)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

Benzyl chloroformate is the benzyl ester of chloroformic acid. It is also known as benzyl chlorocarbonate and is an oily liquid whose color is anywhere from yellow to colorless. It is also known for its pungent odor. When heated, benzyl chloroformate decomposes into phosgene and if it comes in contact with water it produces toxic, corrosive fumes.

It is prepared in the lab by dropping benzyl alcohol into liquid phosgene at −20 °C. Phosgene is used in excess to minimise the production of the carbonate.

Benzyl chloroformate is used in organic synthesis for the introduction of the carboxybenzyl (abbreviated Cbz or Z) protecting group for amines:

The newly formed Cbz protecting group can be removed under reductive conditions. Typically hydrogen gas and activated palladium on carbon are used.