cis isomers and especially cis-g-irone
are responsible in the powerful and pleasant
violet-like olfactive properties.
The synthesis of irones has attracted considerable attention over the last 20 years.
The cis-g-irone's syntheses, excepted one, are not stereoselective and consequently the major product is trans-g-irone. Moreover, these isomers are not separated on a preparative scale.
Summary: There are 5 cis-g-irone's
syntheses, and only one with total stereoselectivity.
Which are the difficulties?
a) The introduction of cis stereochemistry .
b) Diastereoisomers intermediates are rarely separated.
Our Solutions to the synthesis:
The different syntheses are based upon 4 strategies: (see below, and click on a pathway)