Hatsuo Maeda

Reactions of acyl tributylphosphonium chlorides and dialkyl acylphosphonates with Grignard and organolithium reagents

Abstract Ketones and esters ( 4 ) were effectively prepared by reaction of Grignard reagents with acyl tributylphosphonium chlorides ( 2 ), diethyl acylphosphonates ( 5 ), or diisopropyl acylphosphonate ( 6 ) derived from acid chlorides and chloroformates ( 1 ). Although by the method with 2 , 4 is prepared in one-pot operation from 1 and generally in a higher yield, the method with 5 or 6 proved to compensate for the synthesis of 4 with 2 in some respects. The reactivities of 2 , 5 , and 6 as electrophiles were also evaluated by comparing their reduction potentials with those of acid chlorides.

Reactions of in situ formed acyl tributylphosphonium ions with Grignard reagents as an effective route to ketones from acid chlorides

Abstract The reactions of acyl tributylphosphonium ions in situ generated from acid chlorides and Bu 3 P in THF at −22°C with primary alkyl and arylmagnesium halides have proved to be a convenient and simple procedure to prepare ketones from acid chloride in one-pot.

One-step transformation of α-amino acids to α-amino aldehydes effected by electrochemical oxidation of Ph3P

Abstract The electrolysis of triphenylphosphine and L-α-amino acids in one compartment cell under a nitrogen atmosphere at −30°C gave L-α-amino aldehydes in good yields with no or little racemization when triphenylphosphonium perchlorate was used as a supporting electrolyte.

Electrochemical generation and reactions of acyloxytriphenylphosphonium ions

Abstract Constant-current electrolysis, in an undivided cell, of Ph3P in the presence of a carboxylic acid in CH2Cl2 containing 2,6-lutidinium perchlorate as the supporting electrolyte was shown to generate the corresponding acyloxyphosphonium ion, Ph3P+-OCOR, which was converted in situ to esters, amides, and β-lactams under mild conditions.

TRANSFORMATION OF ACID CHLORIDES INTO ALDEHYDES BY REDUCTION OF IN-SITU FORMED ACYLTRIBUTYLPHOSPHONIUM IONS WITH ZINC-COPPER COUPLE OR ZINC

Abstract Transformation of acid chlorides into the corresponding aldehydes without over-reduction to alcohols was effectively achieved by the reduction of acyltributylphosphonium ions, formed in-situ from the chlorides and tributylphosphine in CH 3 CN, with ZnCu couple or Zn in the presence of CH 3 SO 3 H under an N 2 atmosphere.

One-step deoxygenation of alcohols into alkanes by a 'double electrolysis' in the presence of a phosphine

Abstract Deoxygenation of primary and secondary alcohols was effectively achieved in one-step by constant current electrolysis of a mixture of a phosphine, an alcohol, and Et4NBr in CH3CN with one compartment cell at room temperature under N2 atmosphere.

Generation of acyl anion equivalents by in situ cathodic reduction of acyl tributylphosphonium ions anodically generated from tributylphosphine and carboxylic acids: preparation of α-hydroxy cycloalkanones from keto acids

The preparation of α-hydroxy cycloalkanones from keto acids was effectively achieved by constant current electrolysis in the presence of Bu3P in an undivided cell under an N2 atmosphere, where the α-oxy ylides generated by the in situ cathodic reduction of acyl tributylphosphonium ions, formed anodically from tributylphosphine and carboxylic acids, seems to function as a novel acyl anion equivalent.

Intramolecular Wittig reaction of α,α'-dioxocycloalkylidenetributylphosphoranes: formation and trapping of cycloalkyn-2-ones with five- and six-membered rings

Reaction of the title phosphoranes with homophthalic anhydride or 1,3-diphenylisobenzofuran in the presence of Me3SiCl gave the corresponding Diels–Alder adducts, indicating the transient intermediacy of cycloalkyn-2-ones with five- and six-membered rings.

Reduction of benzoyl tributylphosphonium chlorides by samarium diiodide as a novel access to 4-benzoylbenzaldehydes

Addition of samarium diiodide to a well-stirred THF solution of benzoyl tributylphosphonium chlorides generated in situ from benzoyl chlorides and tributylphosphine at −40 °C gave 4-benzoylbenzaldehydes as predominant products from benzoyl chlorides without para-substituents, while benzoyl chloride bearing p-methyl or chloro groups was exclusively converted into the corresponding α-diketone.

Reactions of Electrochemically Generated Alkoxy Phosphonium Ions

Reactions of alkoxy triphenylphosphonium salts (1), prepared by a simple electrochemical procedure from primary and secondary alcohols, with nucleophiles indicated that a soft nucleophile is apt to attack at the α -carbon to give the corresponding Sn2 product, while a hard one at the phosphorus atom to regenerate the original alcohol. Thermal decomposition of 1 with BF4 - as counter anion has been shown to afford alkyl fluorides. One-pot dehydroxysubstitution reactions at the anomeric carbons of protected sugars has been effected via in situ decomposition of the corresponding electrochemically generated alkoxy phosphonium ions.