36847-51-5Relevant articles and documents
Base-promoted diastereoselective α-alkylation of borane: N -((S)-1′-phenylethyl)azetidine-2-carboxylic acid ester complexes
Tayama, Eiji,Nishio, Ryotaro,Kobayashi, Yoshiaki
supporting information, p. 5833 - 5845 (2018/08/22)
The base-promoted α-alkylation of N-((S)-1-phenylethyl)azetidine-2-carboxylic acid esters 1 was investigated. The use of diastereomerically pure borane complexes 3 as substrates, which are easily prepared from 1, dramatically improved the yields and diastereoselectivities of α-alkylated products 2. For example, the treatment of tert-butyl ester (1S,2S,1′S)-3a with 2.4 equivalents of lithium bis(trimethysilyl)amide (LiHMDS) at 0 °C followed by 2.6 equivalents of benzyl bromide afforded α-benzylated (2S,1′S)-2aa in 90% yield as almost a single diastereomer. Our method enables the production of optically active α-substituted azetidine-2-carboxylic acid esters starting from commercially available (S)-1-phenylethylamine, which is one of the least expensive chiral compounds.
Cobalt-bisoxazoline-catalyzed asymmetric kumada cross-coupling of racemic α-bromo esters with aryl grignard reagents
Mao, Jianyou,Liu, Feipeng,Wang, Min,Wu, Lin,Zheng, Bing,Liu, Shangzhong,Zhong, Jiangchun,Bian, Qinghua,Walsh, Patrick J.
supporting information, p. 17662 - 17668 (2015/02/02)
The first cobalt-catalyzed asymmetric Kumada cross-coupling with high enantioselectivity has been developed. The reaction affords a unique strategy for the enantioselective arylation of α-bromo esters catalyzed by a cobalt-bisoxazoline complex. A variety of chiral α-arylalkanoic esters were prepared in excellent enantioselectivity and yield (up to 97% ee and 96% yield). The arylated products were transformed into α-arylcarboxylic acids and primary alcohols without erosion of ee. The new enantioenriched α-arylpropionic esters synthesized herein are potentially useful in the development of nonsteroidal anti-inflammatory drugs. This method was conducted on gram-scale and applied to the synthesis of highly enantioenriched (S)-fenoprofen and (S)-ar-turmerone.
Synthesis of the cytotrienin A core via metal catalyzed C-C coupling
Roessle, Michael,Del Valle, David J.,Krische, Michael J.
supporting information; experimental part, p. 1482 - 1485 (2011/05/15)
A synthetic approach to the C17-benzene ansamycins via metal catalyzed C-C coupling is described. Key bond formations include direct iridium catalyzed carbonyl crotylation from the alcohol oxidation level followed by chelation-controlled Sakurai-Seyferth dienylation to form the stereotriad, which is attached to the arene via Suzuki cross-coupling. The diene-containing carboxylic acid is prepared using rhodium catalyzed acetylene-aldehyde reductive C-C coupling mediated by gaseous hydrogen. Finally, ring-closing metathesis delivers the cytotrienin core.
AZETIDINE ANALOGUES OF NUCLEOSIDASE AND PHOSPHORYLASE INHIBITORS
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Page/Page column 25, (2008/12/07)
Azetidine analogues of nucleosidase and nucleoside phosphorylase inhibitors having the general formula (I), the use of these compounds as pharmaceuticals, pharmaceutical compositions containing the compounds, methods of treating certain diseases using the compounds, processes for preparing the compounds, and intermediates useful in the preparation of the compounds wherein W and X are each independently selected from hydrogen, CH2OH, CH2OQ and CH2SQ; Y and Z are each independently selected from hydrogen, halogen, CH2OH, CH2OQ, CH2SQ, SQ, OQ and Q; Q is an alkyl, aralkyl or aryl group each of which may be optionally substituted with one or more substituents selected from hydroxy, halogen, methoxy, amino, or carboxy; R1 is a radical of the formula (II) or R1 is a radical of the formula (III) A is selected from N, CH and CR2, where R2 is selected from halogen, alkyl, aralkyl, aryl, OH, NH2, NHR3, NR3R4 and SR5, where R3, R4 and R5 are each alkyl, aralkyl or aryl groups optionally substituted with hydroxy or halogen, and where R2 is optionally substituted with hydroxy or halogen when R2 is alkyl, aralkyl or aryl; B is selected from hydroxy, NH2, NHR6, SH, hydrogen and halogen, where R6 is an alkyl, aralkyl or aryl group optionally substituted with hydroxy or halogen; D is selected from hydroxy, NH2, NHR7, hydrogen, halogen and SCH3, where R7 is an alkyl, aralkyl or aryl group optionally substituted with hydroxy or halogen; E is selected from N and CH; G is a C1-4 saturated or unsaturated alkyl group optionally substituted with hydroxy or halogen, or G is absent; or a tautomer thereof, or a pharmaceutically acceptable salt thereof, or an ester thereof, or a prodrug thereof.
SYNTHESIS OF THE TRIETHYL ESTERS OF 1-HALOGENOBUTANE-1,4,4-TRICARBOXYLIC ACIDS
Incze, M.,Soti, F.,Szantay, Cs.
, p. 267 - 272 (2007/10/02)
A method of preparation of triethyl 1-chloro- and 1-bromobutane-1,4,4-tricarboxylate is described.
