Palladium Catalyzed Allylation of Indole

Regioselective N-allylation and N-cinnamylation of indoles using CuI-exchanged hierarchical nanoporous material

“…In sharp contrast to entries 2 and 3, the use of Cu I Y affords 68% of N-allylated product however along with the notable amount of C-3 allylated product. We have extended our present investigation into the cinnamylation of indoles also, which was actually failure to achieve by the Pd/PPh 3 system [15] and the interesting results are presented in table 2.…”

“…Similarly selective synthesis of C-3 allylated indoles includes the use of catalysts such as H 2 SO 4 [10], Ru [11], amberlyst-15 [12], Et 3 B [13], Pd [14][15]. Recently, N-allylation of amines and O-allylation of phenols have been reported with allyl acetate using Pd Catalyst [16][17].…”

Rapid Assembly of Functionalised Spirocyclic Indolines by Palladium‐Catalysed Dearomatising Diallylation of Indoles with Allyl Acetate

“…Whilst there is good precedent for the Pd-catalysed allylation of indoles with a range of allyl sources, [14][15][16][17][18] and even for the dearomatising allylation of 3substituted indoles with allyl carbonates, with allyl alcohols in combination with organoboranes [15] or by rearrangement of Nalloc protected indoles, [14,[19][20][21][22] the direct use of allyl acetate in such reactions has proved challenging to date. [23] Although highly activated allylic esters containing two conjugated aromatic rings can be successfully used in Pd-catalysed allylation reactions, [24] there is only a single report of the Pd-catalysed reaction of indole 1 a with allyl acetate 2, and the reaction was reported to produce a relatively complex mixture of N and C allylated products 3 a-6 a from which 3-allylindole 4 a was isolated in up to 54 % yield. [23] Allyl acetate is a considerably cheaper starting material than the carbonates and carbamates typically employed, because it is a bulk chemical that can be prepared on an industrial scale by direct acetoxylation of propene.…”

“…[23] Although highly activated allylic esters containing two conjugated aromatic rings can be successfully used in Pd-catalysed allylation reactions, [24] there is only a single report of the Pd-catalysed reaction of indole 1 a with allyl acetate 2, and the reaction was reported to produce a relatively complex mixture of N and C allylated products 3 a-6 a from which 3-allylindole 4 a was isolated in up to 54 % yield. [23] Allyl acetate is a considerably cheaper starting material than the carbonates and carbamates typically employed, because it is a bulk chemical that can be prepared on an industrial scale by direct acetoxylation of propene. [25] Therefore, we decided to explore whether it could be successfully employed in the direct Pd-catalysed diallylation of indole.…”

Palladium‐Catalyzed Direct Cyclopropylation of Heterocycles

“…An alternative pathway involving external attack of an indole on p-allylpalladium complexes is less likely.Itwould have led to allylation at C3, more nucleophilic site of indole. [28] We wondered how aC À Hb ond of benzoxazole could be cleaved under the reaction conditions.When benzoxazole was stirred with NaOMe and 10 equivalents of [D 4 ]methanol, it underwent facile H-D exchange at room temperature by reversible deprotonation (Scheme 4e). [29] TheH-D exchange process was accompanied by partial ring opening of benzox- azole.T he ring-opened form existed as an isonitrile (34 % yield;N MR) in a [ D 6 ]benzene solution.…”