2-(Trimethylsilyl)ethoxymethyl chloride

2-(Trimethylsilyl)ethoxymethyl chloride (SEM-Cl) is an organochlorine compound with the formula C₆H₁₅ClOSi, which was developed by Bruce H. Lipshutz during his work on the synthesis of N-methylmaysenine. It is used to protect hydroxyl groups, which can be cleaved with fluoride in organic solvents selectively under mild conditions.^[1] Typically tetrabutylammonium fluoride and caesium fluoride can be used as deprotection reagents. Alternatives such as magnesium bromide,^[2] lithium tetrafluoroborate and boron trifluoride etherate were also developed to deprotect SEM group.^[3]

2-(Trimethylsilyl)ethoxymethyl chloride

Identifiers
CAS Number	76513-69-4 Y
3D model (JSmol)	Interactive image
ChemSpider	2006421
ECHA InfoCard	100.071.328
EC Number	278-483-4
PubChem CID	2724271
CompTox Dashboard (EPA)	DTXSID10227327
InChI InChI=1S/C6H15ClOSi/c1-9(2,3)5-4-8-6-7/h4-6H2,1-3H3 Key: BPXKZEMBEZGUAH-UHFFFAOYSA-N
SMILES C[Si](C)(C)CCOCCl
Properties
Chemical formula	C6H15ClOSi
Molar mass	166.72 g·mol−1
Appearance	Colorless liquid[1]
Boiling point	57–59 °C (330–332 K) (8 mmHg)[1]
Hazards
GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H226, H314
Precautionary statements	P210, P233, P240, P241, P242, P243, P260, P264, P280, P301+P330+P331, P303+P361+P353, P304+P340, P305+P351+P338, P310, P321, P363, P370+P378, P403+P235, P405, P501
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references