A Biomimetic Synthesis of α-Methylene-γ-Butyrolactones

Stereoselective synthesis and application of isopulegol-based bi- and trifunctional chiral compounds

“…1). [69][70][71][72][73][74] Nucleophilic addition of primary amines to a-methylene-gbutyrolactone 4 has proved to be an efficient method for the preparation of a highly diversied library of b-aminolactones 5-8. 58,75 Treatment of b-aminolactones with LiAlH 4 resulted in secondary aminodiols 9-12.…”

Synthesis and Transformation of (-)-Isopulegol-Based Chiral β-Aminolactones and β-Aminoamides

“…The key intermediate (+)- α -methylene- γ -butyrolactone 2 was prepared from commercially-available (-)-isopulegol 1 with regioselective hydroxylation, followed by two-step oxidation and ring closure of the obtained γ -hydroxy-substituted α , β -unsaturated carboxylic acid by applying literature methods [ 23 , 24 , 25 , 26 , 27 , 28 ] ( Figure 1 ). The diastereoisomeric (-)- α -methylene- γ -butyrolactone 4 was prepared by starting similarly from (-)-isopulegol 1 .…”

“…The diastereoisomeric (-)- α -methylene- γ -butyrolactone 4 was prepared by starting similarly from (-)-isopulegol 1 . In the first step, the hydroxy group of 1 was oxidized, followed by stereoselective reduction of the resulting carbonyl group providing (+)-neoisopulegol 3 [ 23 , 24 , 25 , 26 , 27 , 28 , 29 ] ( Figure 1 ).…”

Stereoselective syntheses and application of limonene- and isopulegol-based bi- and trifunctional chiral ligands

“…The key intermediate (+)--methylene--butyrolactone 190 was prepared from commercially available (-)-isopulegol 188 with regioselective hydroxylation, followed by two-step oxidation and ring closure of the obtained -hydroxy-substituted ,-unsaturated carboxylic acid applying literature methods. [111][112][113][114][115][116] Diastereomeric (-)--methylene--butyrolactone 192 was prepared in a similar way starting from (-)-isopulegol 188. In the first step, the hydroxy group of 188 was oxidized followed by stereoselective reduction of the resulting carbonyl group providing (+)-neoisopulegol 191 (Scheme 35).…”

“…In the first step, the hydroxy group of 188 was oxidized followed by stereoselective reduction of the resulting carbonyl group providing (+)-neoisopulegol 191 (Scheme 35). [111][112][113][114][115][116][117] Scheme 35. Synthesis of (-)-isopulegol-based -methylene--butyrolactone 190 and 192…”