New compounds identified in agarwood (Aquilaria agallocha Roxb.)

Four new compounds have been isolated from agarwood oil (Aquilaria agallocha Roxb.) and their structures confirmed by synthesis: (1R,2R,6S,9R)-6,10,10-trimethyl-ll-oxatricyclo[7.2.1.0^1,6]dodecane-2-spiro-2′-oxirane (1) (epoxy-β-agarofuran), (1S,2S,6S,9R)-6,10,10-trimethyl-11-oxatricyclo[7.2.1.0^1,6]dodecane-2-carbaldehyde (2), (E)-8,10-undecadien-2-one (3) and 2,t-3-dimethyl-r-2-(3-methyl-2-butenyl)-l-cyclohexanone (4, absolute configuration unknown). Several of their diastereoisomers, such as (1R,2S,6S,9R)-6,10,10-trimethyl-11-oxatricyclo [7.2.1.0^1,6]dodecane-2-spiro-2′-oxirane (5), (1S,2R,6S,9R)-6,10,10-trimethyl-11-oxatricyclo[7.2.1.0^1,6] dodecane-2-carbaldehyde (6), (Z)-8,10-undecadien-2-one (7) and racemic 2,c-3-dimethyl-r-2-(3-methyl-2-butenyl)-1-cyclohexanone (8, racemate) were also synthesized and fully characterized. The ¹³C NMR data of agarospirol (9), published earlier,¹are corrected. The assignments are supported by 1D-INADEQUATE experiments.