First Total Synthesis of Cryptolaevilactones, Unique Spiromeroterpenoids

Cryptolaevilactones (CLs) A–L ( 1 – 12 ), twelve previously isolated spiromeroterpenoids, feature a unique spiro[3.5]nonene skeleton formed from a polyketide chain and a monoterpene. CLs A–C and L ( 1 – 4 ) are diastereomers with different configurations at three chiral centers around a spiro moiety. Herein, we reported the first total syntheses of 1 – 3 via a convergent strategy accomplished through the construction of three components, a styryl group, a lactone chain, and a spiro ring moiety (isopropylspiro[3.5]nonenone). In this study, the previously unreported compound 13 (CL N) was identified as a natural product from Cryptocarya laevigata .