| abstract |
An enantioselective synthesis of orlistat precursor δ-lactone is provided. A process for preparing a δ-lactone: a process in which an acyl halide is treated with a ketene acetal, via (IV) or via (VI). [R 1 : C 1 -C 20 alkyl; R 2 : H, C 1 -C 10 alkyl; R 3 : hydroxy protecting group; R 4 and R 5 in formula (IV): C 1 -C 6 alkyl, C 5 -C 20 aryl, C 6 -C 20 arylalkyl, -SiR 8 R 9 R 10 ( R 8, R 9, R 10: C 1 -C 6 alkyl, phenyl); R 6: H, R 4; (VI ) formula R 5: C 1 -C 6 alkyl, C 5 -C 20 aryl, C 6 -C 20 arylalkyl; R 7: H, R 3 ] [Selection figure] None |