Studies On The Total Synthesis Of Benzooxygen Heterocyclic Natural Products With Optically Activities

Benzo-oxygen heterocyclic natural products have abundant sources, complex structures, huge numbers and obvious biological activities in the nature, since being discovered, they have become the focus researches of organic synthesis, and have got important applications in the field of medicine, pesticide and materials.This paper studies on the benzo-1,3-dioxole, dihydrobenzochromeno and dihydrobenzofurans three kinds of natural products, first total synthesis of some optically active compounds, and then confirms the absolute configurations.For the benzo-1,3-dioxole natural products, take the phenylpropanoids 2-1 as the research object. Take Evans Aldol reaction to construct chiral center, natural product 2-1 and its enantiomer were synthesized for the first time. Chiral auxiliary groups were used in the Evans Aldol reaction, which makes the enantiomers can be separated by column chromatography. Absolute configuration(R) of natural product 2-1 was determined by crystal data of its derivative. NMR data were analysed, some error carbon signals were corrected, omission carbon signals were supplied, optical information was modified.In the total synthesis of dihydrobenzochromeno natural products, take 2,4-dihydroxybenzaldehyde as material, by using Evans Aldol reaction to construct chiral center, natural product 3-1 and its enantiomer were stereoselectivity synthesized for the first time, and starting from natural product 3-1 to synthesize natural products 3-2, 3-3, 3-4, and the derivative 3-5.Through the comparison of NMR and optical rotation datas, eventually confirmed the absolute configuration of natural product 3-1 and 3-2 are(S), natural product 3-4 is(R). And then, correct the NMR solvent of natural product 3-1 to CDCl3.In the study of dihydrobenzofurans natural products, by using 2,4-Dibromophenol as material, by opening chiral epoxy and carbonyl nucleophilic addition to construct chiral centers, natural product 4-1 and 4-2 were stereoselectivity synthesized for the first time, and then natural products and derivative 4-3 to 4-9 were synthesized.For natural product 4-1, after detailed reasoning, presumably out the natural product should be the mirror isomer of compound(2R, 12S)-4-1, and the absolute configuration should be(2S, 12R). Same to natural product 4-2, the related attributions were determined by 2D NMR, base on others work,presumed that the absolute configuration should be the same as that of compound(2S, 11 R, 12S)-4-2.For natural product 4-7, through the comparison of NMR and optical rotation datas, finally confirmed its absolute configuration is(R). In the data contrast of natural products 4-8 and 4-9 found that the structures are likely to be wrong in the literature, and based on existing work the possible structure of natural product is proposed, and verification work for this conjecture was completed.Fifteen natural products and derivatives,sixty-six intermediates which were synthesized in this paper, were given the structure characterizations by 1H NMR, 13 C NMR, IR and MS.