Cycloalkylation 3-lactone synthesis

Lactones are among the most abundant substructures in natural products." This fact had kindled enormous activity in the field of y-lactone synthesis." 7-Lactones have been prepared by direct cycloacylation of 7-hydroxy acids, eiAer as such or generated as transient intermediates, and by cycloalkyl ation, either of 7-halocarboxylates or of 3,7- or 7,S-unsaturated acids by additions to the double bond. 

Cycloalkylation (7, 148).2 Cycloalkylation of 2 with (Z)-l was used as one step in a total synthesis of (+ )-sesbanine (6), a constituent of Seshania drummondii seeds with antileukemic activity. The hydroxyl group was introduced into the cyclopentene ring of 4 by iodolactonization followed by reduction to give 5. Final steps included aminolysis of the lactone ring, intramolecular addition of the amide anion to the CN group, and hydrolysis to give 6. 

Alkyl, cycloalkyl, arylalkyl acids and their derivatives. A facile, diastereoselective synthesis of highly functionalized y-lactone phosphonate esters (76) has been achieved in the reaction of trifluoromethylated-1,3-diones with dimethyl acetylenedicarboxylates in the presence of triphenyl... 

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