Yoshinao Tamaru

Arylation and vinylation of 2-carboethoxyethylzinc iodide and 3-carboethoxypropylzinc iodide catalyzed by palladium

Abstract By the palladium catalysis 2-carboethoxyethylzinc iodide reacts with aryl iodides and vinyl iodides or triflates to provide the coupling products (ethyl 3-arylpropionates and ethyl 4-pentenoates, respectively) in satisfactory yields. The similar coupling reaction is obserbed for the reaction with 3-carboethoxypropylzinc iodide.

Generation of 2-Carboethoxyethylzinc iodide and 3-carboethoxypropylzinc iodide and their application to the synthesis of γ- and δ-keto esters

Abstract 2-Carboethoxyethylzinc iodide and 3-carboethoxypropylzinc iodide are generated by the reaction of the corresponding iodoesters with Zn-Cu couple and utilized for the palladium catalyzed coupling reaction with acid chloride to quantitatively provide gamma- and delta- keto esters, respectively.

Novel catalytic reactions involving π-allylpalladium and -nickel as the key intermediates: umpolung and β-decarbopalladation of π-allylpalladium and nickel-catalyzed homoallylation of carbonyl compounds with 1,3-dienes☆

Abstract Three subjects concerning novel reactions involving π-allylpalladium and π-allylnickel as intermediates are reviewed: the first is the umpolung of π-allylpalladium, an alternation of the electrophilic nature of π-allylpalladium species into the nucleophilic one of allylzinc species, which proceeds by treating the π-allylpalladium with diethylzinc. Unique regio- and stereoselectivity of the thus-formed allylzincs toward carbonyl compounds is described. The second is the ring-opening reaction of 5-vinyl-2-oxa-1-palladacyclopentane intermediates, which furnishes aldehydes and ketones in good yields. The reaction proceeds via a novel C–C bond cleavage β to the palladium (decarbopalladation reaction). Finally, the nickel-catalyzed homoallylation of carbonyl compounds with 1,3-dienes is discussed. The reaction is promoted by triethylborane or diethylzinc and tolerates carbonyl compounds (alkyl-, arylaldehydes and ketones) and 1,3-dienes, of a wide structural variety. The reaction provides 1,2- and 1,3-disubstituted 4-pentenols with high 1,2- and 1,3-diastereoselectivity. Mechanistically, this final reaction is closely related, in a reverse manner, to the decarbopalladation reaction (second subject).

Nickel‐Catalyzed Homoallylation of Aldehydes and Ketones with 1,3‐Dienes and Complementary Promotion by Diethylzinc or Triethylborane

Regio- and stereoselective homoallylation of saturated aldehydes and ketones to give bishomoallyl alcohols 1,3-anti-1 is achieved with [Ni(acac)2 ] (cat.) and Et2 Zn [Eq. (a)]. This new catalyst system thus complements the previously reported combination of [Ni(acac)2 ] with Et3 B, which offers advantages in the homoallylation of unsaturated and aromatic aldehydes. acac=acetylacetonato.

Pd·Et3B-catalyzed alkylation of amines with allylic alcoholsElectronic supplementary information (ESI) available: experimental section. See http://www.rsc.org/suppdata/cc/b2/b210920d/

A combination of catalytic amounts of Pd (0.05 mmol) and Et3B (0.3 mmol) promotes allylic alkylation of primary and secondary aromatic and aliphatic amines (1.0 mmol) by the direct use of allylic alcohols, providing tertiary amines in excellent yields under mild conditions (room temperature approximately 50 degrees C).

Palladium catalyzed oxycarbonylation of 4-penten-1,3-diols: efficient stereoselective synthesis of cis 3-hydroxytetrahydrofuran 2-acetic acid lactones

Abstract cis 3-Hydroxytetrahydrofuran acetic acid lactones have been prepared selectively and in high yield by an intramolecular palladium catalyzed oxycarbonylation of 4-penten-1,3-diols under mild conditions (room temperature, 1 atm of CO).

A convenient and efficient unsymmetrical ketone synthesis from acid chlorides and alkyl iodides catalyzed by palladium

Abstract Unsymmetrical ketones are prepared in good or excellent yields by a palladium catalysed coupling reaction of acid chlorides and alkyl iodides mediated by Zn-Cu couple.

Et3B-promoted, Pd(0)-catalyzed allylation of active methylene compounds with allylic alcohols

Abstract Triethylborane promotes the Pd(0)-catalyzed allylation of active methylene compounds (Meldrum’s acid and malonates) with a variety of allylic alcohols. The reaction proceeds smoothly at room temperature and provides the allylation products in good yield.

Et3B–Pd-promoted allylation of benzaldehyde with allylic alcohols

In the presence of Pd(OAc)2 (0.05 equiv.) and PPh3 (0.1 equiv.), triethylborane promotes a variety of allyl alcohols to undergo allylation of benzaldehyde to provide homoallyl alcohols in good yield.

Unsymmetrical ketone synthesis via palladium catalyzed carbonylation of organic halides

Abstract Aryl alkyl (or benzyl) ketones are selectively prepared by the reaction of aryl iodides and alkyl iodides (or benzyl chlorides) in the presence of a stoichiometric amount of zinc-copper couple and a catalytic amount of palladium(0) complex under an atmospheric pressure of carbon monoxide.