Selective Catalytic C–H Alkylation of Alkenes with Alcohols

Abstract

Alkenes and alcohols are among the most abundant and commonly used organic feedstock in industrial processes. We report a selective catalytic alkylation reaction of alkenes with alcohols that forms a carbon-carbon bond between vinyl carbon-hydrogen (C-H) and carbon-hydroxy centers with the concomitant loss of water. The cationic ruthenium complex [(C(6)H(6))(PCy(3))(CO)RuH](+)BF(4)(-) (Cy, cyclohexyl) catalyzes the alkylation in solution within 2 to 8 hours at temperatures ranging from 75° to 110°C and tolerates a broad range of substrate functionality, including amines and carbonyls. Preliminary mechanistic studies are inconsistent with Friedel-Crafts-type electrophilic activation of the alcohols, suggesting instead a vinyl C-H activation pathway with opposite electronic polarization.

Synthesis of 2-substituted tryptophans via a C3- to C2-alkyl migration

“…More recently, direct C2-arylation and alkylation of N -protected tryptophan methyl ester have been reported in the context of a more extensive study on C−H activation reactions [58–61]. The present procedure is comparable to those described previously in terms of yield, but it is superior to previous methods with respect to its simplicity as it employs easily accessible 3-substituted indoles.…”

Molecular iodine as a mild catalyst for cross-coupling of alkenes and alcohols

“…The majority of known methods include the use of very effective transition metal catalysts, such as complexes of Pd, Cu, Ni, Fe, Ru and Lewis acids based on weak metals (e.g. Bi, In and Ga) [7][8][9][10][11][12][13][14][15][16][17]. However, toxicity of organometallic reagents and their removal to meet the strict specifications of pharmaceutical grade purity is a challenging and demanding process.…”

Clean and selective catalytic C-H alkylation of alkenes with environmental friendly alcohols

“…In response to this open challenge, Yi et al reported a selective catalytic alkylation reaction of alkenes with alcohols using a well-defined Ru-complex [(C 6 H 6 )(PCy 3 )(CO)RuH] + BF 4 -(1; Cy, cyclohexyl) as catalyst (see Scheme 1) [15]. The reaction was carried out using a broad range of substrate functionality, including amines and carbonyls, for 2 to 8 hours at temperatures ranging from 75° to 110°C [16].…”