175522-76-6Relevant articles and documents
Enantioselective Terpene Syntheses by Diels-Alder Reaction of 1-(1-Arylalkoxy)-2-methyl-1,3-butadiene with Isoprene
Zadel, Guido,Rieger, Rainer,Breitmaier, Eberhard
, p. 1343 - 1346 (2007/10/02)
The (R)- and (S)-1-(1-arylalkoxy)-2-methyl-1,3-butadienes 6 undergo cycloadditions with excess isoprene (7) under pressure to yield not only the expected (4S,6R)- and (4R,6S)-trans-carveol (8) with up to 96percent e.e. but also up to 40percent of (R)- and (S)-limonene (9) with up to 93percent e.e.Asymmetric induction is proposed to arise from a transition state involving definite ? stacking of one molecule of isoprenyl ether and two molecules of isoprene.Key Words: (4S,6R)-, (4R,6S)-trans-Carveol / (R)-, (S)-Limonene / Isoprene / Isoprenyl ether / Cycloaddition, diastereo-, enantioselective