Masahiko Isaka

General synthesis of cyclopropenones and their acetals

Abstract Metalated cyclopropenone acetals 5 react with a variety of electrophiles, including alkyl halides, carbonyl compounds, vinyl iodides, vinyl triflates, and aryl iodides, to give substituted cyclopropenone acetals in high yield. Hydrolysis of the acetal under acidic conditions gives the corresponding cyclopropenone. The reaction sequence has realized an efficient synthesis of an antibiotic penitricin ( 1 ).

Me3SiCl-assisted 1,2-addition of organocuprates to carbonyl compounds

Abstract Me 3 SiCl not only accelerates the 1,2-additions of organocopper reagents to carbonyl compounds, but also enhances the Cram diastereoselectivity of the addition to a chiral aldehyde.

One-pot synthesis of substituted cyclopropenone ketals via alkylation of 3,3-dialkoxy-2-sodiocyclopropenes

Abstract A variety of substituted cyclopropenone ketals have been prepared by electrophilic trapping (protonolysis and alkylation) of sodium salts of cyclopropenone ketals that have been generated directly from the ketals of 1,3-dichloroacetone derivatives through cyclization with NaNH 2 in a liq. NH 3 /ether mixture.

Synthesis of Cyclopropenone-Containing Amino Acid Mimic. Addition of Cyclopropenyl Cerium Reagent to α-Amino Aldehydes

Abstract A novel amino acid mimic, 2-(2-amino-1-hydroxyalkyl)-cyclopropenone, has been prepared via chelation controlled addition of a cyclopropenyl cerium reagent to an α-amino aldehyde.