A new convergent synthesis of (±)‐methyl jasmonate based on a C4 + C6 synthon approach

A new, convergent synthesis of (±)‐methyl jasmonate is presented. The strategy is based on a C4+C6 synthon approach. The C4 fragment N,4,4‐trimethoxy‐N‐methyl‐butanamide (5) was prepared in 4 steps starting from chloroacetyl chloride via the previously unreported N,4,4‐trimethoxy‐N‐methylbut‐2‐enamide (4). The coupling of 5 with the C6 synthon, cis‐3‐hexenyl magnesium chloride (6), provided easy access to (Z)‐4‐oxodec‐7‐enal (8). The latter was converted to the key intermediate (Z)‐2‐(pent‐2‐en‐1‐yl)cyclopent‐2‐en‐1‐one (9) from which (±)‐methyl jasmonate can be obtained in high yield using well‐established procedures. A new, convergent synthesis of (±)‐methyl jasmonate is presented. The strategy is based on a C4 + C6 synthon approach. The C4 fragment (5) was prepared in 4 steps starting from chloroacetyl chloride. The coupling of 5 with the C6 synthon, cis‐3‐hexenyl magnesium chloride (6), provided an easy access to (Z)‐4‐oxodec‐7‐enal. The latter was converted to the key intermediate (Z)‐2‐(pent‐2‐en‐1‐yl)cyclopent‐2‐en‐1‐one (9) from which (±)‐methyl jasmonate can be obtained in high yield by well established procedures.