Taek Hyeon Kim

Synthesis of ethyl 3-cyano-2-methylcinnamates and 3-cyano-2-methylcinnamonitriles from the Baylis–Hillman acetates

Abstract The reaction of the DABCO salts 2 , generated in situ from the Baylis–Hillman acetates 1 , and KCN in aqueous THF gave ethyl 3-cyano-2-methylcinnamates 4a – d and 3-cyano-2-methylcinnamonitriles 4e – f in good yields.

Synthesis of 1,3-disubstituted naphthalenes from the Baylis–Hillman acetates with the aid of manganese(III) acetate

Abstract 1,3-Disubstituted naphthalene derivatives can be easily synthesized from Baylis–Hillman acetates by successive reaction: (1) SN2′ type reaction with diethyl malonate or ethyl nitroacetate; (2) manganese(III) acetate-assisted radical cyclization and (3) aromatization with NaI/O2 system or elimination of nitrous acid.

Melt free‐radical grafting of hindered phenol antioxidant onto polyethylene

A monomeric antioxidant (3) was prepared by reacting 3,5-di-tert-butyl-4-hydroxybenzyl alcohol (1) with N-[4-(chlorocarbonyl) phenyl] maleimide (2). This reactive antioxidant was grafted onto polyethylene (PE) by melt processing with free-radical initiators in a mini-max molder. The IR spectra of the grafted PE showed that the monomeric antioxidant was introduced onto the PE. IR spectroscopic methods and titration were used for the quantitative determination of the extent of grafting of the monomeric antioxidant. Also, the extent of crosslinking was indicated by the gel content. Grafting occurred in the following order: dicumyl peroxide (DCP) > benzoyl peroxide > 2,2′-azobisisobutyronitrile. The influences of the DCP concentration and monomeric antioxidant on the extent of grafting were studied. The effects of the reaction time and temperature were also determined.

A mild cyclodesulfurization of N-(2-hydroxyethyl)-N′-phenylthioureas to 2-phenylamino-2-oxazolines using TsCl/NaOH

Abstract An efficient synthesis of 2-phenylamino-2-oxazolines 3 via cyclodesulfurization of N-(2-hydroxyethyl)-N′-phenylthioureas 2 by a one-pot reaction using p-toluenesulfonyl chloride (TsCl) and NaOH in very good yields is described.

L-Valinol and L-phenylalaninol-derived 2-phenylamino-2-oxazolines as chiral auxiliaries in asymmetric alkylations

Lithium enolates of N-acyl phenyliminooxazolidine auxiliaries reacted with alkyl halides to produce the α-alkylated products with very high diastereofacial selectivity (up to >99% d.e.). The products were readily cleaved by simple alkaline hydrolysis to give homochiral carboxylic acids and could also be directly converted to aldehydes and other acid derivatives such as esters and amides.

Efficient synthesis of 2-methylaminothiazolines via Mitsunobu reaction of N-(2-hydroxyethyl)-N′-methyl-thioureas

Abstract 2-Methylaminothiazolines 3 were synthesized selectively from N -(2-hydroxyethyl)-thioureas 2 by the intramolecular Mitsunobu reaction.

l-Valinol and l-phenylalaninol-derived 2-imidazolidinones as chiral auxiliaries in asymmetric aldol reactions

Abstract The chiral N -propionyl-2-imidazolidinones were synthesized in three steps from l -valinol and l -phenylalaninol and the aldol reaction of their boron enolate with aldehydes proceeded with high diastereoselectivity.

N-Acyl-4,5-dihydro-4,4-dimethyl-N-methyl-2-thiazolamine as a chemoselective acylating agent

2-Methylamino-2-thiazoline reacted with alkyl acyl halides to produce N-acyl-2-methylamino-2-thiazolines, exo-acylated product regioselectively, which were found to be highly chemoselective acylating agents for primary amine in the presence of secondary amine and for the less sterically hindered of two different primary amines.

A Practical Synthesis of β-Keto Phosphonates from Triethyl Phosphonoacetate

Abstract An efficient and practical preparation of β-keto phosphonates, via acylation reaction of triethyl phosphonoacetate with carboxylic acid chlorides in the presence of magnesium chloride-triethylamine followed by decarbethoxylation, is described.

One-pot synthesis of 2-phenylaminothiazolines from N-2-hydroxyethyl)-N′-phenylthioureas

Abstract 2-Phenylaminothiazolines 3 were synthesized from N -(2-hydroxyethyl)- N′ -phenylthioureas 2 by a one-pot reaction using p -toluenesulfonyl chloride (TsCl) and NaOH or Et 3 N.