Pheromone Synthesis, CLI. Synthesis of Chlorinated Steroids Related to the Structures Proposed for Blattellastanosides A and B, the Aggregation Pheromone of the German Cockroach, Blattella germanica L.
Remote functionalization of 5α-stigmastan-3β-ol (5) to yield eventually 5α-stigmast-9(11)-en-3α-ol (8) was employed for the syntheses of 9α-chloro-5α-stigmastane-3β,11β-diol (13) and 12α-chloro-9α,11α-epoxy-5α-stigmastan-3β-yl β-D-glucopyranoside (3). The former (13) was the aglycone part of the structure 2 originally proposed for blattellastanoside B, and the latter (3) was exactly the structure proposed for blattellastanoside A, the components of the aggregation pheromone of the German cockroach, Blattella germanica L. The present work disproved the structures 1–4 proposed for blattellastanosides A and B.