Convergent synthesis and structural confirmation of phellodonin and sarcodonin ε.

The first synthesis of members of the sarcodonin family, phellodonin and sarcodonin ε, is reported herein. This verifies that the unprecedented and seemingly unstable N,N-dioxide-containing benzodioxazine framework can be constructed in the laboratory and lends further support to the proposed structures. The key step in the synthesis involves a biomimetic hetero-Diels-Alder reaction between a pyrazine N-oxide and an ortho-quinone.