Number of electrophilic centres in the given compound is ______

An electrophilic centre is an electron-deficient atom that is susceptible to attack by a nucleophile.

In the given compound, three electrophilic centres are present.

The carbonyl carbon $$\mathrm{(C=O)}$$ is electrophilic because oxygen is more electronegative than carbon and pulls electron density towards itself.

Thus, the carbonyl carbon acquires a partial positive charge:

$$\mathrm{C^{\delta +}=O^{\delta -}}$$

The $$\mathrm{\beta}$$-carbon of the alkene is also electrophilic because the double bond is conjugated with the carbonyl group, forming an:

$$\mathrm{\alpha,\beta\text{-}unsaturated\ ketone}$$

Due to resonance, electron density shifts towards oxygen, creating partial positive character at the $$\mathrm{\beta}$$-carbon.

Hence, nucleophilic attack can occur at this position.

The nitrile carbon $$\mathrm{(-C \equiv N)}$$ is the third electrophilic centre.

Nitrogen is more electronegative than carbon and withdraws electron density through the triple bond.

Thus, the nitrile carbon becomes electron deficient and electrophilic.

Therefore, the three electrophilic centres are:

$$\mathrm{Carbonyl\ Carbon,\ \beta\text{-}Carbon,\ Nitrile\ Carbon}$$