First total synthesis of triprenylquinones and hydroquinones isolated from endemic nudibranch Leminda millecra, two naturally occurring compounds 5-methyl-2-(2E,6E-3,7,11-trimethyl-2,6-dodecadien-9- onyl)benzo-1,4-quinone (1) and 5-methyl-2-(2E,6E-3,7,11-trimethyl-2,6-dodecadien-9-onyl)-1,4-hydroquinone (2) has been achieved from cheap and available 2-methylhydroquinone (4) and geranyl bromide, involving protection of phenol, bromination, coupling reaction of arylbromide with Grignard reagent catalyzed by Li₂CuCl₄, Julia coupling, etc. Reduction of 1 with NaBH₄, gave one of this kind of natural products, 5-methyl-2-(2E,6E-9-hydroxy-3,7,11-trimethyl-2,6-dodecadienyl)-1,4-hydroquinone (±)-3.

Key words: endemic nudibranch Leminda millecra, total synthesis, catalytic coupling of Li₂CuCl₄, Julia coupling