Pd-catalyzed allylic alkylation of phenylvinylcarbinols with some nucleophiles

Transition metal catalyzed nucleophilic allylic substitution: activation of allylic alcohols via π-allylic species

“…13b M. Sakakibara and Ogawa also reported the use of allylic alkylation directly from alcohol using [Pd(PPh 3 ) 4 ] in refluxing THF for the preparation of key intermediates for the synthesis of estrogen compounds (Scheme 6). 14 Later on, T. Ikariya et al showed that the use of palladium(0) catalysts featuring phosphite ligands such as [Pd{P(OPh) 3 } 4 ] led to good activity in toluene or under neat conditions at 80 1C. 15 With this catalyst, it was possible to perform allylation of aliphatic alcohols, and carbonucleophiles for the formation of diallylated products from NuH 2 (NuH 2 = aniline, cyclic 1,3-diketones and 1,3-diesters) under neutral conditions without prior deprotonation.…”

Catalytic C−C Bond Formation Using a Simple Nickel Precatalyst System: Base‐ and Activator‐Free Direct C‐Allylation by Alcohols and Amines

“…The use of allylic alcohols and amines in such processes represents am ore atomeconomical transformation( since water or ammonia-in the case of primary allylamines-are the by-products), but the lowerr eactivity of these substrates typically demands the presence of stoichiometric amountso fa ctivators (often Brønsted or Lewis acids). [5,6] The abilityo fn ickel complexes to mediate oxidative insertion into CÀOa nd CÀNb onds withoutt he need for activating reagents has led to thesec atalysts being used in allylation using alcohols [7,8] and amines; [7b, 9, 10] to date, the reportedp rocesses using alcohols have required Ni(COD) 2 ,a nd (where mixtures are possible)o ften do not show selectivity for monoallylatedp roducts (Figure 1). [12] We commencedo ur study with two aims:t od evelop a nickel-catalysed method using allyl amines or alcohols which delivered monoallylated products selectively,a nd to devisea meanso fa ccessing the crucial Ni 0 catalysts from an inexpensive, air-stable precursor.W ec hose to use NiBr 2 ·3 H 2 O, one of the most inexpensive nickel salts, [13] as our nickel source, and elemental zinc as the reducing agent (due to its low toxicity compared to other metal reducing agents, such as manganese); as mentioned, key goals of our study were to reduce the amount of reducing agent to al ow level, and to avoid the use of ab ase in the reaction, thereby simplifying still further the process.…”