於本篇論文中，本人成功發展一個不對稱合成路徑以合成a-羥基甲基酯以及其鏡像異構物，應用此不對稱合成子可合成多甲基迷迭香酸及丹酚酸甲、丙和丁。此外，本人亦報導經由五步驟反應，總產率為28%之七甲基紫草酸新型合成路徑，利用鎂金屬於甲醇溶液中進行立體選擇性還原苯并呋喃，建構具有對位位向之二氫苯并呋喃核心結構之七甲基紫草酸。
此類型化合物抗愛滋病毒複製之生物活性亦在本篇探討。其中，多甲基(+)-迷迭香酸以及(±)-丹酚酸丙具有抑制HIV-1RTMF (AZT-resistant)病毒複製之生物活性，其IC50 分別為34 uM 及50 uM。最後，本人用異丁基二甲基矽烷基做為理想之保護基以完成多酚酸之全合成。迷迭香酸之全合成以咖啡酸為起始物可於七個步驟完成，其總產率為42%。並且，此高效率路徑可用以合成oresbiusin B、丹酚酸丙、及丁之骨架。

In this thesis, asymmetric syntheses of methyl lactate and its antipode has been discussed. Application of these chiral synthons culminated in the asymmetric syntheses of both the antipodes of polymethylated rosmarinic acid, salvianolic acid A, salvianolic acid C, and salvianolic acid D. In addition, a modular, flexible, and convergent route to the heptamethyl lithospermic acid has been described. The heptamethyl lithospermic acid was accomplished in 5 steps from the known compounds in 28% overall yield. The trans-dihydrobenzofuran core of heptamethyl lithospermic acid was achieved by stereoselective reduction of benzo[b]furan with magnesium in methanol. Furthermore, an alternative method for the synthesis of trans-cinnamic acid derivative has been devised and can be applicable for enantioselective synthesis of lithospermic acid.
The biological activity of polymethylated caffeic acids against HIV-1 virus replication was evaluated. Among them, polymethylated (+)-rosmarinic acid and (±)-salvianolic acid C were found to inhibit the replication of HIV-1RTMF (AZT-resistant) virus with IC50 values of 34 µM and 50 µM respectively. Also, this thesis presents the total synthesis of polyphenolic acids which exploits tert-butyldimethylsilyl (SiMe2t-Bu) as an ideal protecting group. In order to prove that, total synthesis of (±)-rosmarinic acid was completed in 7 steps and 42% overall yield from caffeic acid. Furthermore, efficient and flexible routes were established for the syntheses of orthogonally protected skeleton of oresbiusin, salvianolic acid C, and salvianolic acid D.

English Abstract.............. i
Chinese Abstract ..............ii
Acknowledgements ............. iii
Contents ..................... iv
Introduction .................... 1
Isolation and Biological Activities of Representative Caffeic Acids ………………. 3
Lithospermic Acid (11) as an Integrase Inhibiton ...... 4
Previous Synthetic Efforts for (R)-Rosmarinic Acid (6)...5
Potential Synthetic Applications of (R)-Rosmarinic Acid (6) ……………………… 7
Previous Synthetic Efforts for Lithospermic Acid (11)... 9
Methoxy Group Responsible for Various Biological Activities ...............11
Results ............... 13
Synthetic Plan for Polymethylated Caffeic Acids ………………………………13
Syntheses of Racemic and (R)-(+)-Methyl Lactate 31 … 14
Syntheses of Racemic, (R), and (S)-Polymethylated Rosmarinic Acid 40 .......... 16
Syntheses of Racemic, (R), and (S)-Polymethylated Salvianolic Acid A 41 ……… 17
Syntheses of Racemic, (R), and (S)-Polymethylated Salvianolic Acid C 42 .......... 23
Syntheses of Racemic, (R), and (S)-Polymethylated Salvianolic Acid D 43 ........... 29
Retrosynthetic Analysis of (+)-Lithospermic Acid (11) .........................33
Synthesis of (±)-trans-Dihydrobenzofuran Cinnamic Acid 70 …………………… 34
Asymmetric Synthesis of (S, S)-Trans-Dihydrobenzofuran Cinnamic Acid 70 ........... 41
Alternative Protecting Group Strategy …………49
Progress towards Total Synthesis of (R)-Oresbiusin B (5) ..............53
Total Synthesis of (±)-Rosmarinic Acid (6) ………… 54
Progress towards Total Synthesis of (R)-Salvianolic Acid C (8) .................... 55
Towards Total Synthesis of (R)-Salvianolic Acid D (9) ………………………….. 58
Antiviral Activity of Polymethylated Caffeic Acids against HIV-1RTMF Replication........... 61

Discussion ........... 64
Decarboxylation at the C3 Position ........... 64
Hydrogenation of Benzo[b]furan Ester......... 64
Magnesium–Methanol Reduction of Benzo[b]furan Ester ....66
Synthesis of (±)-trans-dihydrobenzofuran 80 ........ 66
Antiviral Activity of Polymethylated Caffeic Acids..... 67
Conclusion .............. 71
Experimental Section ........... 72
General Procedure ......... 72
Inhibition of HIV-1 Virus Replication (Materials and Methods ............74
(+)-(R)-Methyl 3-(3,4-Dimethoxyphenyl)-2-hydroxypropanoate ((+)-31 ......... 74
(+)-(R)-Methyl 2-[[(2E)-3-(3,4-Dimethoxyphenyl)-1-oxo-2-propenyl]oxy]-3-(3,4-dimethoxyphenyl)propanoate ((+)-40)...... 76
(R)-Methyl 2-[[3-(3,4-Dimethoxy)-2-(E)-(3,4-dimethoxyphenylethene)-1-oxo-2-propenyl]oxy]-3-(3,4-dimethoxyphenyl)propanoate (41) ………………………… 81
(R)-Methyl 2-[[3-(3,4-Dimethoxy)-2-(Z)-(3,4-dimethoxyphenylethene)-1-oxo-2-propenyl]oxy]-3-(3,4-dimethoxyphenyl)propanoate (56) ………………………… 83
(+)-(R)-Methyl 2-[[3-[2-(3,4-Dimethoxyphenyl)-7-methoxybenzo[b]furan-4-yl]-1-oxo-2-propenyl]oxy]-3-(3,4-dimethoxyphenyl)propanoate ((+)-42) ……………86
(R)-Methyl 2-[[(2E)-3-(3,4-Dimethoxy)-2-(2-methoxy-2-oxoethyl) phenyl)-1-oxo-2-propenyl]oxy]-3-(3,4-dimethoxyphenyl)propanoate ((+)-43) …………………92
(±)-3-[7-Methoxy-2-(3,4-dimethoxyphenyl)-3-methoxycarbonyl-2,3-dihydro-benzo[b]furan-4-yl]propenoic acid (trans-70) ……………………………………99
(+)-(R)-Methyl 3-[3,4-Bis (tert-butyldimethylsilyloxy)phenyl] 2-hydroxypropanoate ((+)-101 .......108
(±)-[[(2E)-3-(3,4-Dihydroxyphenyl)-1-oxo-2-propenyl]oxy]-3,4-dihydroxybenzene propanoicacid (rosmarinic acid) (6) ……………………………………………113
(R)-Methyl 2-[[(2E)-3-(2-Benzyloxy-3-tert-butyldimethylsilyloxy)-2-(2-methoxy-2-oxoethyl)phenyl)-1-oxo-2-propenyl]oxy]-3-(3,4-bis(tert-butyldimethylsilyloxy)
phenyl)propanoate (128) ........ 122
References ........ 124
Spectra of 1H NMR, 13C NMR and HPLC Chromatograms ..... 132

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