Allylic Substitution

Allylic substitution 1 (Pd)

AS1_A

Numerous ligands have been applied to this reaction including ferrocene-based examples (where generally R1 = R2). Links as: alkylation (A, B, C), aminationphosphination, phosphonation.

Allylic substitution 2 (Pd)

AS2

COP-X catalysts are described here. Links as Y = N (A, B, C), Y = S (A), Nu = OCOR2 (A), OAr (A, B).

Allylic substitution 3 (Ir)

AS3

JACS02-124-15164

JACS02-124-15164_A

Phosphoramidite 1.  Excellent regioselectivity (branched : linear typically about 50 : 1, lowest = 11 : 1). With R2 = H typically small quantity of double alkylation (<5%). Lower regioselectivity (6 : 1) with R1 = p-NO2C6H4 (86% ee) and ee = 76% with R1 = o-MeOC6H4.

Angew04-43-2426

Angew04-43-2426

Phosphoramidite 2. Significant acceleration in the reaction rate noted with phosphoramidite 2 compared to phosphoramidite 1.

OL04-6-3529

OL04-6-3529

Phosphoramidite 2. Most R1 substituents gave ≥99 : 1 branched/linear. Lower ration with R1 = Cy (13 : 1) and R1 = n-Pr (4 :1). With R1 = o-MeOC6H4, ee = 79%.