Method for synthesizing 6-methyl-5-octylene-2-ketone through condensation and hydrogenation

The invention provides a method for synthesizing 6-methyl-5-octylene-2-ketone through condensation and hydrogenation. The method takes 3-methyl-2-pentenal and acetone as raw materials, 6-methyl-5-octylene-2-ketone is synthesized through aldol condensation and hydrogenation reaction, and specifically comprises the following steps: under the action of a base catalyst, 3-methyl-2-pentenal and acetone are condensed to obtain a 6-methyl-3, 5-octylene-2-ketone intermediate, and then under the action of a rhodium catalyst, selective hydrogenation is carried out to obtain the 6-methyl-5-octylene-2-ketone. The synthesis route is novel, the raw materials which are simple and easy to obtain are used, and the target product is obtained with high yield through two-step reaction; secondly, in the hydrogenation reaction, the rhodium catalyst is used as a hydrogenation catalyst, so that the regioselectivity is very high; the addition of a silane auxiliary agent can effectively stabilize the rhodium catalyst, maintain the act