Please use this identifier to cite or link to this item: http://hdl.handle.net/11455/34682
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dc.contributor.authorLu, T.J.en_US
dc.contributor.author陸大榮zh_TW
dc.contributor.authorLin, C.K.en_US
dc.date2008zh_TW
dc.date.accessioned2014-06-06T07:48:09Z-
dc.date.available2014-06-06T07:48:09Z-
dc.identifier.issn0022-3263zh_TW
dc.identifier.urihttp://hdl.handle.net/11455/34682-
dc.description.abstractTwo novel chiral monocyclic iminolactones 14a and 14b have been prepared. The chiral auxiliary 12 was obtained from alpha-methyl-trans-cinnamaldehyde through reduction, methylation, Sharpless asymmetric dihydroxylation, and oxidation in 87% overall yield. Esterification of compound 12 with the respective protected amino acids followed by deprotection and cyclization provided the corresponding iminolactones, each in 82% overall yield. Alkylation of the iminolactone 14a afforded the alpha-methyl-alpha,alpha-disubstituted products 15 and 16 in good yields (78-99%) and excellent diastereoselectivity (de >98%). Alkylations of the iminolactone 14b furnished the alpha-benzyl-alpha,alpha-disubstituted products 15a, 16b, 17, and 18 in good yields (51-86%) but moderate diastereoselectivities (43-56%). When HMPA or DMPU was used as a cosolvent, the rate of alkylation of the iminolactone 14b was accelerated with improved yields (56-99%) and diastereoselectivities (50-83%). Hydrolysis of the dialkylated iminolactones yielded the alpha,alpha-disubstituted a-amino acids in good yields (80-98%) and high enantiomeric excesses (98-99%) with good recovery of compound 12 (83-92%).en_US
dc.language.isoen_USzh_TW
dc.relationJournal of Organic Chemistryen_US
dc.relation.ispartofseriesJournal of Organic Chemistry, Volume 73, Issue 24, Page(s) 9527-9534.en_US
dc.relation.urihttp://dx.doi.org/10.1021/jo801514gen_US
dc.subjectdess-martin periodinaneen_US
dc.subjectstereoselective-synthesisen_US
dc.subjectdiastereoselectiveen_US
dc.subjectalkylationen_US
dc.subjectenantioselective additionen_US
dc.subjecttransfer hydrogenationen_US
dc.subjectchiralen_US
dc.subjectligandsen_US
dc.subjectpart 1en_US
dc.subjectglycineen_US
dc.subjectderivativesen_US
dc.subjectaldehydesen_US
dc.titleAsymmetric Synthesis of alpha-Amino Acids: Preparation and Alkylation of Monocyclic Iminolactones Derived from alpha-Methyl trans-Cinnamaldehydeen_US
dc.typeJournal Articlezh_TW
dc.identifier.doi10.1021/jo801514gzh_TW
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