- Concise and practical approach for the synthesis of honokiol, a neurotrophic agent
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An improved method has been developed for the synthesis of honokiol using a readily available p-bromophenol as a precursor. The key step involved in this method is ortho-lithiation facilitated by methoxymethyl ether (MOM). Other important steps are ortho-allyl phenyl ether Claisen rearrangement and a Suzuki coupling for the construction of biaryls. This method does not require pre-functionalization of aromatic ring with bromide for the generation of arylboronic acid.
- Khan, P. Rasvan,Mujawar, Taufiqueahmed,Shankar, G.,Shekhar, P.,Subba Reddy, BV.,Subramanyam, Ravi
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supporting information
(2020/08/06)
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- Enantioselective syntheses of (S)- and (R)-8,9 dihydroxydihydromagnolol
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8,9-Dihydroxydihydromagnolol 5 was synthesized in four steps in which the synthesis of magnolol 4 was improved and the absolute configuration of 5 was confirmed as (R).
- Gu, Wenxin,She, Xuegong,Pan, Xinfu,Yang, Teng-Kuei
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p. 1377 - 1380
(2007/10/03)
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- Synthesis of (-)-Monoterpenylmagnolol and Magnolol
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(-)-Monoterpenylmagnolol (3) was synthesized in eight steps from (+)-3,9-dibromocamphor (4) and the bis(methoxymethyl) ether (22) of 3-(4-hydroxyphenyl)-1-propanol.Fragmentation of an endo-3-aryl-9-bromocamphor (27) provided the correct absolute stereochemistry.In this total synthesis, dissolving metal conditions were developed to reduce enol phosphate and isopropenyl functions without concomitant reduction of an attached phenol.Palladium(0)-catalyzed cross-coupling of an arylzinc chloride with 4-allyl-2-iodophenyl methoxymethyl ether (34) provided the desired tricyclic 1,2,3,5-tetrasubstituted biaryl 41 in fair yield without optimization and with little isomerization of the allyl group.Magnolol (1) was also synthesized by aryl coupling of 34 and the methoxymethyl ether of 4-allyl-2-lithiophenol via the zinc chloride method as above, as well as from 5,5'-dibromo-2,2'-dimethoxybiphenyl (37) by allylation with allyltributylstannane followed by ether cleavage.
- Agharahimi, Mohamad R.,LeBel, Norman A.
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p. 1856 - 1863
(2007/10/02)
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