Process for making β-carotene

A process for preparing β-carotene, represented by Formula 3

• which comprises the steps of
• a) providing a sulfone compound of Formula B
• (b) deprotonating the sulfone compound of Formula B and reacting not more than ½ equivalent, based upon the sulfone compound, of an allylic sulfide, represented by Formula C
• wherein X is a halogen, to provide a sulfide compound of Formula D
• (c) oxidizing the sulfide compound of step (b) to provide a sulfone compound of
• (d) subjecting the sulfone compound of step (c) to a Ramberg-Bäcklund reaction to provide 11,20-di(benzenesulfonyl)-11,12,19,20 tetrahydro-β-carotene of Formula F
• (e) reacting the product of step (d) with a base to obtain β-carotene of Formula 3.