Yali Chen

A Highly Stereoselective Synthesis of 2,3,4,5‐Tetrasubstituted‐trans‐2,3‐dihydrofurans

Abstract α,β‐Unsaturated sulfones derivatives 5 was prepared from sodium p‐toluenesulfinate (1) and the products reacted with substituted‐carbomethoxymethyltriphenylarsonium bromide 6 in the presence of potassium carbonate at room temperature to give cyclopropane derivatives 2‐substituted‐3‐substitutedphenyl‐4‐p‐toluenesulfonyl‐5‐phenyl‐trans‐2,3‐dihydrofurans 7 and/or 8 with high stereoselectivity.

STEREOSELECTIVE SYNTHESIS OF TRANS-β-METHOXYCARBONYL-γ-ARYL-γ-BUTYROLACTONES

ABSTRACT Stereoselective synthesis of trans-β-methoxycarbonyl-γ-aryl-γ-butyrolactones (5) by the reaction of methoxycarbonylmethyl triphenyl arsonium bromide (1) and 2,2-dimethyl-5-substituted-benzal-1,3-dioxa-4,6-dioxa-4,6-dione (2) is carried out in the presence of potassium carbonate and trace water in dimethoxyethane. 1,2-Cis-cyclopropane 3 is formed as an intermediate. The stability of compound 3 in water is related to the property of the aryl substituent. With strong electron-donating groups [2a–c, Ar=4-CH3O‒C6H4; 3,4-OCH2O‒C6H3 or 4-(CH3)2N‒C6H4] at room temperature 3 is formed in situ and transformed to γ-butyrolactones 5a–c immediately, whereas when the aryl substituent is H or a weak electron-donating or electron-withdrawing group (2d–g, Ar=4‒CH3-C6H4; C6H5; 4-Cl‒C6H4 or 4-NO2‒C6H4), 3 is stable to water at room temperature. On further heating in acetone, 3 is transformed to γ-butyrolactones 5d–g (stepwise synthesis). One-pot synthesis of 5d–g from the reaction of 1 with 2d–g is also studied.

An Efficient and Highly Stereoselective Synthesis of CIS-1-Acetyl-2-Aryl-6,6-Dimethyl-5,7-Dioxo-Spiro-[2,5]-4,8-Octadiones and β,γ-Trans-β-Acetyl-γ-Aryl-Butyrolactones

Abstract Acetylmethyltriphenylarsonium bromide 6 in the presence of potassium carbonate and trace water reacted with 2,2-dimethyl-l,3-dioxa-5-substituted-benzylidene-4,6-dione 2 at room temperature to give cyclopropane derivatives cis-l-acetyl-2-aryl-6,6-dimethyl-5,7-dioxospiro-[2,5]-4,8-octadiones 7 (X=p-CH3, p-Cl, H, p-NO2) or β,γ-trans-β-acetyl-γ-aryl-γ-butyrolactones 8 (X=p-CH3O, p-N(CH3)2, 3′,4′-OCH2O-) with good yield and high stereoselectivity.

Study on the Reaction of CIS-1-Acetyl-2-Aryl-6,6-Dimethyl-5,7-Dioxospiro-[2,5]-4,8-Octadiones with Methanol

Abstract Cis-l-acetyl-2-aryl-6,6-dimethyl-5,7-dioxo-spiro-[2,5]-4,8-octadiones 3a-d (X=p-CH3, p-Cl, H, p-NO2) reacted with anhydrous methanol in a sealed tube at 80°C to form trans, cis-α-carbomethoxy-β-(α′-methoxy-α′-aryl)-γ-methoxy-γ-methyl-γ-butyrolactones 4a-d and cis, cis-α-carbomethoxy-β-(α′-methoxy-α′-aryl)-γ-methoxy-γ-methyl-γ-butyrolactones 5a-d in good yield.

THE STEREOSELECTIVE SYNTHESIS OF N-ARYL-TRANS, TRANS-α-CARBOXYL-β-METHOXYCARBONYL-γ-ARYL-γ-BUTYROLACTAMS

Cis-1-methoxycarbonyl-2-aryl-6,6-dimethyl-5,7-diox-spiro-[2,5]-4,8-octadiones (1) in dimethyl ethylene glycol at room temperature react with anilines (2) to give N-aryl-trans,trans-α-carboxyl-β-methoxycarbonyl-γ-aryl-γ-butyrolactams (3) in good to excellent yields and high stereoselectivity.

An Efficient and Highly Stereoselective Synthesis of β,γ-Trans-β-Benzoyl-γ-Aryl-γ-Butyrolactones

Abstract Benzoylmethyltriphenylarsonium bromide 6 in the presence of potassium carbonate reacted with 2,2-dialkyl-1,3-dioxa-5-substituted-benzylidene-4,6-dione 2 at room temperature to give β,γ-trans-β-benzoyl-γ-aryl-γ-butyrolactones 7 in good yield.

The Reaction of Electron-Deficient Cyclopropane Derivatives with Aromatic Amines

Abstract N-Aryl-trans,trans-α-carboxyl-β-benzoyl-γ-aryl-γ-butyrolactams were synthesized in high yields with high stereoselectivity by the reaction of electron-deficient cyclopropane derivatives, cis-1-benzoyl-2-aryl-6,6-dimethyl-5,7-dioxo-spiro-[2 5]-4,8-octadiones, with aromatic amines. The reaction mechanism was proposed.