- Diacyl Disulfide: A Reagent for Chemoselective Acylation of Phenols Enabled by 4-(N,N-Dimethylamino)pyridine Catalysis
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A general and excellent acylation reagent, diacyl disulfide, was uncovered for efficient ester formation enabled by DMAP (4-(N,N-dimethylamino)pyridine) catalysis. This protocol offered a promising synthetic platform on site-selective acylation of phenolic and primary aliphatic hydroxyl groups, which greatly expanded the realm of protecting group chemistry. The importance of the reagent was also reflected by its excellent moisture tolerance, high efficiency, and potential in synthetic chemistry and biologically meaningful natural product modification.
- Liu, Hong-Xin,Dang, Ya-Qian,Yuan, Yun-Fei,Xu, Zhi-Fang,Qiu, Sheng-Xiang,Tan, Hai-Bo
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supporting information
p. 5584 - 5587
(2016/11/17)
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- Total synthesis of enigmazole a from cinachyrella enigmatica. Bidirectional bond constructions with an ambident 2,4-disubstituted oxazole synthon
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The first total synthesis of the cytotoxic marine macrolide enigmazole A has been completed in 22 steps (longest linear sequence). The sensitive, densely functionalized 2,4-disubstituted oxazole fragment was constructed using an efficient Negishi-type cou
- Skepper, Colin K.,Quach, Tim,Molinski, Tadeusz F.
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supporting information; experimental part
p. 10286 - 10292
(2010/09/06)
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- Microwave promoted selective preparation of acetals and esters from aldehydes
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A new selective method of acetalization of aldehydes and cyclic ketones with 1,2-diols or alcohols catalyzed by iodine under microwave irradiation is reported. Depending upon the reaction conditions further oxidation of the arylidene acetals takes place in the system leading to the formation of products like iodoester 2 and hydroxy esters 3, 4 and 5. Both unsubstituted (1a) and substituted arylidene acetal with electron releasing group (1d) give high yield of iodoester 2 (70-80%) whereas the arylidene acetal substituted with an electron withdrawing group such as NO2 (1b) gives a low yield of the corresponding iodoester (2b, 25%).
- Borah, Ruli,Kalita, Dipok J.,Sarma, Jadab C.
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p. 1032 - 1038
(2007/10/03)
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- β-Functionalised radicals in organic synthesis: 2-Acyloxyalkyl radicals from 2-acyloxyalkyl iodides by the tin route
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The reaction of iodoesters 1a-c with electrophilic olefins 2a-d and in situ generated tributyltin hydride (from a substoichiometric amount of tributyltin chloride and an excess of sodium borohydride) in the presence of a catalytic amound of AIBN in ethanol at 0 to 20°C yields the expected coupling products 3aa-3cd. Products 4 resulting from an iodine/hydrogen exchange are also obtained as by-products in variable amounts. The stereochemistry of the coupling reaction is studied: starting from trans-2-iodocyclohexyl acetate (1d) and methyl acrylate (2a) a 1/3 mixture of the corresponding cis/trans diastereoisomers is obtained. This result indicates that the corresponding radical coupling is not stereospecific.
- Foubelo, Francisco,Lloret, Francisco,Yus, Miguel
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p. 5131 - 5138
(2007/10/02)
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