Glyoxylate and arylglyoxal imines based on 12-aminodehydroabietic acid undergo hetero-DielsAlder (Povarov) reaction with ethyl vinyl ether, cyclopentadiene, and indene to give, respectively, methyl (8aR,9R,12aS)-3-aroyl-5-isopropyl-9, 12a-dimethyl-7,8,8a,9,10,11,12,12a-octahydronaphtho[1,2-f]quinoline-9-carboxylates, methyl (7R,10aS,10dR,13aS)-1-aroyl-3-isopropyl-7,10a-dimethyl-2,5,6,6a,7,8,9,10,10a,10d,13,13a-dodecahydro-1H-naphtho[1,2- -7-carboxylates, and methyl (6aS,11bS,11eS,15R,15aR)-6-aroyl-4-isopropyl-11e,15-dimethyl-2,5,6,6a,7,11b,11e,12,13,14,15,15a-1H-dodecahydroindenoChemical modification of known natural matrices may be regarded as an approach to design of novel biologically active substances. We anticipated that introduction of a heterocyclic fragment into a chiral diterpene molecule could give rise to compounds possessing unusual physical and chemical properties (for example, liquid crystals and reagents for asymmetric synthesis), as well as to biologically active compounds with new kinds of activity.In terms of the concept implying synthesis of new useful organic compounds from renewable natural resources [1, 2] we synthesized substituted naphtho-[1,2-f]quinolines incorporating abietane fragments. For this purpose we used the Povarov reaction [3][4][5]. Following this approach we previously synthesized naphtho[1,2-f]quinolines having a diterpene fragment and an aryl group on C 2 in the quinoline ring [6]. In the present work we selected as starting compounds more reactive Schiff bases derived from ethyl glyoxylate and arylglyoxals, taking into account that such imines are known to readily react with dienophiles according to Povarov [7-10]. As dienophiles we used ethyl vinyl ether, cyclopentadiene, and indene.The reaction conditions were optimized using as model process the reaction of cyclopentadiene with Schiff base I (abietic acid numbering) which was reported in preliminary communication [11] (Scheme 1). The reaction smoothly occurred in 2,2,2-trifluoroethanol at room temperature in the presence of boron trifluoride-ether complex as Lewis acid catalyst.We also tried to use other solvents, such as acetonitrile, methylene chloride, and 1,1,1,3,3,3-hexafluoropropan-2-ol. In the first series of experiments we examined solvent effect on the conversion of imine I and yields of the adducts. The reaction was carried out with 3 equiv of cyclopentadiene and 15 mol % of BF 3 · Et 2 O as catalyst. The optimal reaction temperature was 20°C. The reaction at -20°C was slow, whereas elevated temperature (above 20°C) favored tarring due to oligomerization of cyclopentadiene. After 1 h, the reaction was terminated by adding a saturated aqueous solution of sodium hydrogen carbonate. The conversion of I and yields of adducts IIa-IIc were determined by gas chromatography-mass spectrometry, and the structure of diastereoisomers IIa-IIc (purified by column chromatography) was determined by 1 H and