Reaktion #219688

Reaktionsgleichung

i-PrMgCl

LiCl

benzaldehyde

4-bromobenzonitrile

i-PrMgCl

→

4-allylbenzonitrile

Ausbeute 81.0%

Lösungsmittel

THF

Reaktionsbedingungen

Aufarbeitung

1. 1
   Sonstigein good yields (entry 15, 16)

Vorschrift

Highly substituted chloro and methoxy aryl bromides can readily be converted into the desired Grignard reagents 3i, j. After the reaction with ClPPh2 and oxidative work-up, the phosphine oxides 2ia, ja are obtained in good yields (entry 15, 16). This type of compound is of interest in relation with P-ligands for asymmetric catalysis.[5] Also functions like a cyano group are tolerated. Thus, the reaction of 4-bromobenzonitrile in THF at −7° C. leads to the desired arylmagnesium reagent (3d) in only 50% conversion using i-PrMgCl whereas over 90% is observed with i-PrMgCl.LiCl (Scheme 3). The addition of benzaldehyde provides the alcohol 2da in 81% yield whereas allylation of arylmagnesium reagent (3d) with allyl bromide leads to the corresponding 4-allylbenzonitrile in 92% yield (entry 5,6 of Table 1). See FIG. 3 for additional information.

Quelle