Intermediate of lycopene and preparation method of intermediate

A method of preparing 2,6,10-trimethyl-3,5,9-undecatrienyl-1-aldehyde of formula (3), comprising the following three steps:

• Step I:
• 3-methyl-4,4-dialkoxy-1-aldehyde of formula (11) undergoing a Wittig-Horner condensation reaction with tetra-alkyl methylene diphosphonate at temperature of 0˜30° C. in ether solvent or dipolar aprotic solvent and under protection of inert gas in the presence of bases, to produce 4-methyl-5,5-dialkoxy -1-pentenyl-1-phosphoric acid dialkyl ester of formula (10);
• the reaction sequence is described as follows:
• Step II comprises Step II-1 and Step II-2, wherein,
• Step II-1:
• 4-methyl-5,5-dialkoxy-1-pentenyl-1-phosphoric acid dialkyl ester of formula (10) undergoing a rearrangement reaction at temperature of −40˜30° C. in ether solvent or dipolar aprotic solvent and under protection of inert gas in the presence of bases;
• Step II-2:
• adding 6-methyl-5-heptene-2-one of formula (13) to the product of Step II-1 to undergo a Wittig-Horner condensation reaction at temperature of −40˜30° C. in ether solvent or dipolar aprotic solvent and in the presence of bases to produce 2,6,10-trimethyl-1,1-dialkoxy-3,5,9-undecan-triene of formula (12);
• the reaction sequence is described as follows:
• Step III:
• mixing2,6,10-trimethyl-1,1-dialkoxy-3,5,9-undecan-triene of formula (12) with acid catalysts, water and homogeneous solvents to undergo a hydrolysis reaction at the temperature of 10˜35 under protection of inert gas to produce 2,6,10-trimethyl-3,5,9-undecatrienyl-1-aldehyde of formula (3);
• the reaction sequence of Step III is described as follows: