Asymmetric photochemical synthesis of chiral 5-(R)-(l)-menthyloxy-4-cycloaminobutyrolactones

Through photocatalysed regiospecific and stereoselective additions of cyclo amines to 5-(R)-(l)-menthyloxy-2(5H)-furanone (3), chiral 5-(R)-(l)-menthyl oxy-4-cycloaminobutyrolactones were synthesized, In the new asymmetric phot oaddition of compound 3, the N-methyl cyclic amines (4) gave novel chiral C -C photoadducts (5) in 24-50% isolated yields with d. e. greater than or eq ual to 98%. However, the secondary cyclic amines (6) afforded optically act ive N-C photoadducts (7) in 34-58% isolated yields with d. e. greater than or equal to 98% under the same condition, An the synthesized optically acti ve compounds were identified on the bads of their analytical data and spect roscopic data, such as [alpha](589)(20), IR, H-1 NMR, C-13 NMR, MS and elem entary analysis. The photosynthesis of chiral butyrolactones and its mechan ism were discussed in detail.