Syntheses of Methyl Jasmonate and Analogues.

This account corresponds to the presentation given by the main author on the occasion of the 2 Swiss Industrial Symposium in Basel (October 19 , 2018). After a short historical introduction to methyl-jasmonate and methyl-epijasmonate, it essentially focuses on the reported more promising industrial approaches devoted to the synthesis of these naturally occurring odorants isolated from jasmine flowers. Some attempts to simplify these approaches, as well as independent unreported strategies are also presented.

endo/exo stereoselectivity in Diels-Alder reactions of α,β-dialkylated conjugated enals to cyclic 1,3-dienes: intermediates in the synthesis of (-)-β-santalol and its analogs.

Highly exo-selective [4+2] cycloadditions of cyclopenta-1,3-diene 2a to α,β-dialkyl conjugated enals 5 are compared with the analogous endo-favored Diels-Alder reaction of cyclohexa-1,3-diene 7. The exo-stereoselectivity is lower in the homologous case of methylcyclopenta-1,3-diene 9. This diastereoselectivity is discussed either in terms of a retro-homo-Diels-Alder reaction, associated with thermodynamic control, or with respect to either a competing hetero-Diels-Alder/Claisen or Cope domino pathway, or retro-Claisen/retro-hetero-Diels-Alder of the endo-homo-cycloadducts.