Angela Punzi

A direct access to α-diones from oxalyl chloride

Abstract Cross-coupling reactions of oxalyl chloride with organocopper reagents, derived from Grignard reagents, cuprous bromide, and lithium bromide, provide a simple and straightforward method for the synthesis of symmetrical α-diones in very good yields.

ONE-STEP SYNTHESIS OF DIALKYNYL-1,2-DIONES AND THEIR CONVERSION TO FUSED PYRAZINES BEARING ENEDIYNE UNITS

Abstract A convenient procedure for the preparation of symmetrically end-protected dialkynyl-1,2-diones 3 from lithium acetylides and oxalyl chloride in the presence of CuBr and LiBr is described. The condensation of 3 with various aromatic and heteroaromatic 1,2-diamines leads to pyrazine-based α-dialkynylated heterocycles. The enediyne substructure of diethynylquinoxaline can be thermally rearranged in a Bergman cyclization reaction.

A new straightforward and general approach to dienamide natural products

A new synthetic approach to various conjugated (E,E) dienamides has been developed, starting from an easily accessible bifunctional dienyl compound and based upon a double selective electrophilic substitution, followed by coupling reactions.

A general and straightforward approach to α,ω-ketoesters

Abstract Chemoselective cross-coupling reactions of monoesters of dicarboxylic acid chlorides with organocopper reagents derived from Grignard reagents, cuprous bromide, and lithium bromide, provide a simple and straightforward method for synthesizing a variety of ketoesters.

New synthesis of leukotriene B3 methyl ester from bis(trimethylsilyl) unsaturated derivatives

Abstract A new synthesis of leukotriene B3 methyl ester is reported, starting from bis(trimethylsilyl) unsaturated derivatives as building blocks for the triene moiety of the leukotriene. The two stereogenic centers have been generated by enantioselective chemical reduction of two acetylenic ketones with both R- or S-Alpine BoraneR. The three conjugated double bonds system of the leukotriene has been assembled by Miyaura-Suzuki cross-coupling reaction.

Novel Synthetic Approach to (S)-Coriolic Acid

Abstract A new synthetic approach to (S)-coriolic acid 1 has been developed, starting from the readily available (E)-1-bromo-2-trimethylsilylethene 4 and trimethylsilylacetylene 5. A simple acylation reaction of 4, followed by a coupling reaction of the halogenoderivative intermediate with 5 in the presence of a Pd(0) catalyst affords the monosilylated ketoenyne 7. After desilylation of 7, enantioselective reduction of the carbonyl group with (S)-BINAL-H leads to the alcohol 2 (e.e.=94%). A subsequent coupling reaction and stereoselective reduction of the triple bond affords the target molecule 1.

A straightforward synthesis of substituted cyclopentenones

Abstract A new synthetic approach to substituted silylated cyclopentenones has been developed, starting from an easily accessible bis-silylated conjugated dienyne and based upon the reactions with unsaturated acyl chlorides.

A simple procedure for the synthesis of enantiopure α-acetoxy ketones

Abstract Cross-coupling reactions of α-acetoxy carboxylic acid chlorides with organocopper reagents, derived from Grignard reagents, cuprous bromide and lithium bromide, provide a simple and straightforward method for the synthesis of enantiopure α-acetoxy ketones.

A stereoselective synthesis of silylated polyunsaturated halides from α,β-epoxysilanes

Abstract A new synthetic approach to silylated polyunsaturated halides has been developed, starting from the readily available (1 E ,3 E )-1,4-bis(trimethylsilyl)-1,3-butadiene and (3 E )-1,4-bis(trimethylsilyl)-3-buten-1-yne. A simple epoxidation reaction, followed by regioselective α-opening of the epoxide ring by metal halides affords the corresponding halohydrins with a high degree of stereoselectivity. A subsequent β-elimination reaction from these compounds leads to ( Z , E )-dienyl halides and to ( Z )-enyne halides.

A STRAIGHTFORWARD SYNTHESIS OF SYMMETRICAL POLYENDIYNES BY DIMERIZATION REACTIONS OF SILYL DERIVATIVES

Abstract A straightforward synthesis of polyendiynes is described. The method is based upon a simple dimerization reaction of silylated enynes in the presence of copper salts. A variety of polyunsaturated compounds have been obtained in high yields and with high retention of configuration.