3-acetoxy-1,3-diphenyl-1 propene

CHAIN ELONGATION OF ALKENES via gem-DIHALOCYCLOPROPANES l,l-DIPHENYL-2-BROMO-3-ACETOXY-l-PROPENE... 

Die Palladium-katalysierte Allylierung der Enolate von achiralem N-Alkyliden-glycin (s.S. 492) verlauft mit 3-Acetoxy-l-propen und optisch-aktiven, Phosphan-Liganden tra-genden Palladium-Katalysatoren2 stereoselektiv zum entsprechenden 2-(Diphenyl-me-thylenamino)-4-pen ten saure-Derivat3-5. 

L PROLYLGLYCYLGLYCINE,At CARBO BEN ZOXY-3-HY DROXYETHYL ESTER [GLYCINE,N [AT 13-HYDROXY 1 -[ (PHENYLMETH-OXY)CARBONYL] -L PROLYL] GLYCYL] -, ETHYL ESTER], 88 Propane, 1-mtro-, 36 1,3 Propanedithiol, 9 Propanoic acid, 2-chloro-, 70 1-PROPENE, 3 ACETOXY-2-BROMO-1,1-D1PHENYL- [2-PROPFN-l-OI, 2-BROMO 3,3 DIPHENYL, ... 

Another more specific characteristic can allowed the differentiation between homogeneous and colloidal catalysts. In Pd-catalysed allylic alkylation rac-3-acetoxy-1,3-diphenyl-l-propene with dimethyl malonate, homogeneous and colloid species reacts at different rates with both substrate enantiomers, obtaining in the case of Pd colloids an excellent kinetic resolution (see Section 4) [44]. 

Scheme 1. Asymmetric allylic alkylation of rac-3-acetoxy-l,3-diphenyl-l-propene (rac-I) with dimethyl malonate catalysed by Pd/1 colloidal system. (Reprinted from Reference [44], 2004, with permission from American Chemical Society.)...

PROPENE, 3-ACETOXY-2-BROMO-U-DIPHENYL-, 56, 32 Propene, /Ey-l-bromo-, 55, 108 Propene, ( Z/l-bromo-, 55, 108 Propene, fEM-chloro-, 55, 104, 107 Propene, (Z)- -chloro-, 55,107... 

Alkylation of sodium 1-(alkoxycarbonyl)methyIphosphonates proceeds equally with acetates in THF from low to room temperature or in DME at reflux. The asymmetric allylic alkylation of the sodium diethyl l-(ethoxycarbonyl)methylphosphonate with 3-acetoxy-l,3-diphenyl-l-propene and cyclic allylic acetates in the presence of a chiral palladium catalyst, prepared from chiral phosphine and palladium acetate, in THF at room temperature proceeds in good yields (44-88%) and high ec s. ... 

Table 3.3 Asymmetric allylic alkylation of (rac)-(E)-3-acetoxy-l,3-diphenyl-l-propene catalysed by [(ld)Pd (n3-C3H5)]PF6.

The formation of palladium nanoparticles by reduction with H2 in THF in the presence of a chiral diphosphine based on xylose (6.94) allowed small sized, monodispersed particles to be obtained . These Pd nanoparticles have proven to be good asymmetric catalysts for the CC coupling reaction in the alkylation of (rac)-3-acetoxy-l,3-diphenyl-1-propene by dimethylmalonate under basic conditions (Figure 6.72). 

The substitution of a leaving group located at an allylic position by a nucleophile, catalysed by a transition metal complex, is known as allylic substitution. Unlike most of the transition metal-catalysed reactions, allylic substitution involves reaction at sp rather than sp centres. As an example, the reaction with the most studied substrate, rac-3-acetoxy-l,3-diphenyl-1-propene (11), is depicted in Scheme 8.4. 

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