Nickel-catalyzed alkylation of ketones and nitriles with primary alcohols.

Nickel(II)-salen or nickel(II)-salphen catalyzed α-alkylation of ketones and nitriles with primary alcohols is reported. Various α-alkylated ketones and nitriles were obtained in high yields through a borrowing hydrogen strategy by using 1-3 mol% of nickel catalyst and a catalytic amount of NaOH (5-10 mol%) under aerobic conditions.

Tuning the selectivity in iridium-catalyzed acceptorless dehydrogenative coupling of primary alcohols.

An acceptorless dehydrogenative coupling of primary alcohols to carboxylic acids/carboxylates, esters, and Guerbet alcohols (via both homo- and cross-ß-alkylation of the alcohols) in the presence of an N-heterocyclic carbene iridium(I) catalyst was developed under aerobic conditions. The product selectivity can be easily tuned among the products with a single catalyst through simple modification of the reaction conditions, such as the catalyst and base amounts, the choice of base, and the reaction temperature.

Synthesis of α-Alkylated Ketones via Selective Epoxide Opening/Alkylation Reactions with Primary Alcohols.

A new method for converting terminal epoxides and primary alcohols into α-alkylated ketones under borrowing hydrogen conditions is reported. The procedure involves a one-pot epoxide ring opening and alkylation via primary alcohols in the presence of an N-heterocyclic carbene iridium(I) catalyst, under aerobic conditions, with water as the side product.

Iridium-Catalyzed Alkylation of Secondary Alcohols with Primary Alcohols: A Route to Access Branched Ketones and Alcohols.

Under borrowing hydrogen conditions, NHC-iridium(I) catalyzed the direct or one-pot sequential synthesis of α,α-disubstituted ketones via the alkylation of secondary alcohols with primary alcohols is reported. Notably, the present approach provides a new method for the facile synthesis of α,α-disubstituted ketones and featured with several characteristics, including a broad substrate scope, using easy-to-handle alcohols as starting materials, and performing the reactions under aerobic conditions. Moreover, the selective one-pot formation of ß,ß-disubstituted alcohols was achieved by the addition of an external hydrogen source to the reaction mixture.

Iridium(I)-Catalyzed C-C and C-N Bond Formation Reactions via the Borrowing Hydrogen Strategy.

Iridium(I) complexes having an imidazol-2-ylidene ligand with benzylic wingtips efficiently catalyzed the ß-alkylation of secondary alcohols with primary alcohols and acceptorless dehydrogenative cyclization of 2-aminobenzyl alcohol with ketones through a borrowing hydrogen pathway. The ß-alkylated alcohols, including cholesterol derivatives, and substituted quinolines were obtained in good yields by using a minute amount of the catalyst with a catalytic amount of NaOH or KOH under the air atmosphere, liberating water (and H2 in the case of quinoline synthesis) as the sole byproduct. Notably, this system demonstrated turnover numbers of 940 000 (for ß-alkylation of secondary alcohols with primary alcohols by using down to 0.0001 mol % = 1 ppm of the catalyst) and 9200 (acceptorless dehydrogenative cyclization of 2-aminobenzyl alcohol with ketones).

Iridium(I)-Catalyzed Alkylation Reactions To Form α-Alkylated Ketones.

A highly effective and green procedure for the formation of α-alkylated ketones has been disclosed via the reaction of primary alcohols with secondary alcohols and ketones by using [IrCl(COD)(NHC)] complexes as a catalyst. Various α-alkylated ketones were obtained in high yields from the alkylation of alcohol with alcohol and ketone with alcohol through a borrowing hydrogen reaction by using 0.05-0.5 mol % iridium(I) and a catalytic amount of KOH (5-10 mol %) as the base under air atmosphere and within very short reaction times.