Silylation is the introduction of one or more (usually) substituted silyl groups (R₃Si) to a molecule. Silylations are core methods for production of organosilicon chemistry. Silanization involves similar methods but usually refers to attachment of silyl groups to solids.^[1]

Alcohols, carboxylic acids, amines, thiols, and phosphates can be silylated. The process involves the replacement of a proton or an anion with a trialkylsilyl group, typically trimethylsilyl (-SiMe₃), as illustrated by the synthesis of a trimethylsilyl ethers from alcohols and trimethylsilyl chloride (Me = CH₃):

ROH + Me₃SiCl → ROSiMe₃ + HCl

Generally a base is employed to absorb the HCl coproduct.

Bis(trimethylsilyl)acetamide ("BSA", Me₃SiNC(OSiMe₃)Me is an efficient silylation agent. The reaction of BSA with alcohols gives the corresponding trimethylsilyl ether, together with acetamide as a byproduct (Me = CH₃):^[2]

2 ROH + MeC(OSiMe₃)NSiMe₃ → MeC(O)NH₂ + 2 ROSiMe₃

Silylation has two main uses: manipulation of functional groups and preparation of samples for analysis.

Coordination complexes with silyl ligands are well known. An early example is CpFe(CO)₂Si(CH₃)₃, prepared by silylation of CpFe(CO)₂Na with trimethylsilyl chloride. Typical routes include oxidative addition of Si-H bonds to low-valent metals. Metal silyl complexes are intermediates in hydrosilation, a process used to make organosilicon compounds on both laboratory and commercial scales.^[7][8]

• Silyl ether
• Hydrosilylation