Secondary Metabolites, Monoterpene–Polyketides Containing a Spiro[3.5]nonane from Cryptocarya laevigata

Six novel lactone derivatives, cryptolaevilactones A–F (1–6), were isolated from Cryptocarya laevigata. Their unique spiro[3.5]­nonane moiety by hetero [2 + 2] cyclization with monoterpene and polyketide was found for the first time in nature. Structural elucidation using various nuclear magnetic resonance (NMR) techniques revealed that 1–3 and 4–6 are diastereomers and partially established the absolute configurations.