76699-06-4Relevant articles and documents
High Acceleration and Improved Diastereoselectivity of Intramolecular Ene-Type Reactions by Diethylaluminum Chloride
Oppolzer, Wolfgang,Robbiani, Christian
, p. 2010 - 2014 (1980)
The pyrrolidines 2 and 10 were obtained by thermal ene-reactions at +70 deg and +180 deg from the (Z)-4-aza-1,6-diene 1 and from the (E)-4-aza-1,6-diene 9 in the ratios of 75:25 and 50:50, respectively.On the other hand, these cyclizations proceeded readily in the presence of diethylaluminum chloride at -78 deg and -35 deg giving in high yield the trans-pyrrolidine 2 from 1 with 100percent and from 9 with 89percent diastereoselectivity.
Stereospecific, R2AlCl-Promoted Intramolecular Ene Reaction of a 1,6-Dienoate: Evidence for a Concerted Mechanism
Oppolzer, Wolfgang,Mirza, Sohail
, p. 730 - 738 (2007/10/02)
Treatment of the 83percent-trans-13CH3-labelled 1,6-dienoate 7 with Et2AlCl at -78 deg C provided in high yield the ene product 9 containing 83percent 13C localized in the olefinic C(8)-methylene group.Accordingly, H-transfer occurs exclusively from the trans-methyl group of 7, consistent with a concerted ene process 7->9 thereby ruling out an intermediate cation 8 (Scheme 4).
Synthetic studies in the α-kainic acid (2,3-trans,3,4-cis-2-carboxy- 4-isopropenylpyrrolidin-3-ylacetic acid) series
Kennewell, Peter D.,Matharu, Saroop S.,Taylor, John B.,Sammes, Peter G.
, p. 2542 - 2548 (2007/10/02)
The synthesis of (±)-cis- and (±)-trans-4- isopropenylpyrrolidin-3-ylacetic acids and the attempted synthesis of (±)-2,3-trans,3,4-cis-2-carboxy-4-isopropenylpyrrolidin-3-ylacetic acid, α-kainic acid, by intramolecular ene reactions are described. The ene cyclisation reaction has been shown to be kinetically controlled with the relative stabilities of the transition states controlling the product distribution. No isomerisation of starting diene or product pyrrolidine occurs under the conditions of the reaction.
