A Versatile Hexadiene Synthesis by Decarboxylative sp³–sp³ Coupling/Cope Rearrangement

Transition Metal-Catalyzed Decarboxylative Allylation and Benzylation Reactions

“…66 In the DcA, the γ-position is selectively allylated in preference to the α-position to afford product 47 in modest yield. While simple dienolates derived from β-ketoesters give rise to selective α-allylation, 24 the incorporation of the diene within a pyran moiety may alter the electronics such that γ-allylation is preferred.…”

Assembly of Terpenoid Cores by a Simple, Tunable Strategy

“…Using a variant of Tunge's decarboxylative allylation we were able to convert 9 a to the 1,5‐diene 9 b bearing a tetrasubstituted olefin (Scheme B). It should be pointed out that the decarboxylative method is essential to generating the more substituted Knoevenagel adduct's allyl anion as standard deprotonation conditions results in deprotonation from the less substituted γ‐position (see many of the schemes above).…”

Migratory Decarboxylative Coupling of Coumarins: Synthetic and Mechanistic Aspects

“…[12] Allylation and decarboxylation would then produce 2 a. Lastly, the observation of the diallylated product (2 m', Scheme 1) suggested that the allylation of the methyl group might be proceeding through an a-allylation/Cope rearrangement mechanism (path c, Scheme 2). [13] The mechanism illustrated by path c (Scheme 2) is easily probed, since such a mechanism predicts that a substituted allyl ester will react to form the branched allylated product rather than the linear product. [5e, 14] To test this, the coumaryl cinnamyl ester 1 n was treated with Pd catalyst [Eq.…”

“…Lastly, the observation of the diallylated product ( 2m’ , Scheme 1) suggested that the allylation of the methyl group might be proceeding via an α-allylation/Cope rearrangement mechanism (path c, Scheme 2). 13 …”

“…After allylation, decarboxylation of the carboxylic acid is catalyzed by Pd(0), contrary to more commonly observed Pd(II)-catalyzed decarboxylations. 2,5,13 …”