MOM (methoxymethyl) is a well known and useful protecting group, however the usual way of introducing the MOM group requires the use of MOM-Cl which is a regulated carcinogen.  This paper describes an alternative method for making MOM-protected carbamates that avoids the use of MOM-Cl by forming the MOM-protected carbamate directly using formaldehyde and trimethylsilyl chloride (TMS chloride) – see Scheme.

The MOM group can be readily removed by treatment with 2 equivalents of p-CH₃C₆H₄SO₂Na and 2.5 equivalents of HCl in acetonitrile at room temperature.  In one example where the MOM group is removed in the presence of a Boc group 76% yield of the Boc protected compound was isolated.

D.M. Barnes et al (Abbott), Org. Lett., 2009, 11, 273.