Terpenes juvenile hormone, active

Juvabione is a terpene-derived ketoester that has been isolated from various plant sources. There are two stereoisomers, both of which occur naturally with R-configuration at C(4) of the cyclohexene ring and are referred to as erythro- and f/trao-juvabione. The 7(.S )-cnan(iomcr is sometimes called epijuvabione. Juvabione exhibits juvenile hormone activity in insects that is, it can modify the process of metamorphosis.18... 

Let us look first at a molecule that has been synthesized in a number of alternative ways. Juvabione is a terpene-derived keto ester that has been isolated from certain plant species. It exhibits juvenile hormone activity that is, it can modify the process of metamorphosis in certain insects. At least nine syntheses of this molecule have been completed. 

Juvabione is a terpene-derived ketoester that has been isolated from various plant sources. It exhibits juvenile hormone activity in insects that is, it can modify the process of metamorphosis. 

For Instance, many terpene derivatives mimic insect hormone actioa Juvabione (15) is the classical example of a juvenile hormone (JH) mimic that prevents egg maturation in Pyrrhocoris bugs. Aromatic terpene ethers (16), methylene dloxyphenyl terpene ethers (17), and other farnesyl derivatives also have JH activity and the latter ones (18) also cause sterility in Pyrrhocoris. For the most part JH active terpenes are among the sesquiterpenes but several monoterpenes also have insect sterilizing effects (19. 20). The acyclic monoterpene cltral reduces the fertility of rats by causing follicular degeneration (21). 

A number of compounds important to animal physiology have been identified as isoprenoid compounds. Notable examples are vitamin A, retinal (Section 28-7), and squalene (Table 30-1). Also, terpene hydrocarbons and oxygenated terpenes have been isolated from insects and, like famesol, show hormonal and pheromonal activity. As one example, the juvenile hormone isolated from Cecropia silk moths has the structure shown in 3 ... 

Once the structure was known, many syntheses were reported and all of a sudden the literature was loaded with stereoselective methods for olefin synthesis. Although it is only a guess, it is probable that the discovery of Cecropia juvenile hormone (CJH) was responsible (in part) for this burst of activity. Another reason would be the interest in carbocycle synthesis via polyolefin cyclizations (the development of steroid and terpene chemistry) which slightly preceeded the discovery of CJH, We will start by looking at the Trost group synthesis (the first synthesis) of CJH and then examine several other syntheses wherein the focus... 

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