Palladium catalyzed C-allylation of nitroalkanes

Palladium-catalysed reactions of alcohols. Part B: Formation of C–C and C–N bonds from unsaturated alcohols

“…84). 151 this method led to an unselective reaction, but with triethylamine and lithium chloride as additional additives, the a-allylation of the aldehyde has been carried out with a high yield (Eq. 93); 165 the use of these additives with 2-hydroxymethyl-2-propen-1-ol as allylating agent led to cyclic hemiacetals (Eq.…”

Rapid Decarboxylative Allylation of Nitroalkanes

“…The cinnamaldehyde is most likely derived from the O -allyl nitronate via elimination (Scheme 2). 6 Thus, in the case of 1h , we observe less O -allylation at higher catalyst loading. This suggests that palladium plays a direct role in conversion of the O -allylated intermediate ( B ) to the C -allylated product ( 2h ).…”

“…It is also noteworthy that the cinnamyl derivative 1h performed better under conditions at higher catalyst loadings (10 mol %); at 5 mol % a significant amount of cinnamaldehyde was formed instead of desired allylated nitroalkane (1.5:1 2h :RCHO) 6. The cinnamaldehyde is most likely derived from the O -allyl nitronate via elimination (Scheme 2).…”

“…While there are numerous publications on the use of highly stabilized nitroenolates (pK a ~ 8 in DMSO) in Tsuji-Trost type allylations,5 there are currently few effective methods for allylating nonstabilized nitronates (pK a ~ 17 in DMSO) 6,7. An extensive early study showed that even moderately sterically demanding nitronates suffer from competing O -allylation and thus low yields of C -allylation products 6.…”

“…An extensive early study showed that even moderately sterically demanding nitronates suffer from competing O -allylation and thus low yields of C -allylation products 6. More recently, Shibasaki developed an improved procedure to facilitate C -allylation, however that reaction requires base additives and long (48 h) reaction times at 50 °C for most substrates 7…”