Bondline / Reactions

Epoxidation with a peroxyacid

The alkene attacks the weak O–O bond of a peroxyacid in one concerted step, so both C–O bonds form on the same face (stereospecific: cis stays cis). Drawn with peracetic acid; mCPBA works the same way.

Addition to alkenes · 1 step

Conditions

mCPBA in CH₂Cl₂, room temperature.

Mechanism

Red curly arrows show where each pair of electrons moves.

OOHOOOOH++
MechanismAll in one step: the π bond attacks the outer oxygen, which bonds to both carbons; the O–O bond breaks and the proton moves to the carbonyl oxygen.

About addition to alkenes reactions

The π electrons of a C=C are exposed and electron-rich, so alkenes react with electrophiles. The two new groups add across the double bond.

Practise this mechanismDraw the curly arrows yourself and Bondline checks each one. Or add it to your notes and watch it in 3D.

Open in Bondline