Titanium complexes of sulfonyl amino acid Diels-Al -

nrzxfquxq

Titanium complexes of sulfonyl amino acid Diels-Alder reaction of catalytic enantioselective

Diene cycloaddition reaction of enantioselective catalysis Tab. 1TheEnantic ~ electiveCatalysisoftheComplexesofTitaniumwithN-tosyl-L-aminoAcidsintheDiels-AiderReacti0nofeyclopentadienewithmethylacrylatea selective advantage for the S-type products. ~ {J Yang issued so ChineseJoumalof0gcChemistry397 Table 2 in naphthalene sulfonyl amino methyl acrylate titanium complexes with cyclopentadiene cycloaddition reaction of enantioselective catalysis Tab. 2neEnantioselectiveCatalysisoftheComplexesofTitaniumt} IN ONE (1 a naphthalenesulfonyl1 an L-aminoAcidsfortheDiels _MderReactionofcyclopentadienet} Imethylacrylatea selective advantage of a product for the S-type. It can be seen from Table 1, amino acids and a 2:1 ratio of titanium when the enantioselectivity ratio 1: 1, much better. In sulfonyl as tosyl case, when the ratio of amino acid and titanium 1:1, e.e. value of less than 3O%, the best enantioselectivity of proline, The e.e. value of 27%. When the ratio of amino acid and titanium increased to 2:1, e.e. value more than doubled, but the proline exception, tosyl proline Taiwan titanium material catalyst ee. the value of improved little. Naphthalenesulfonyl titanium complexes of amino acids enantioselectivity than tosyl amino acids complexes of titanium is much better (see Table 2). the ratio of amino acid and titanium 2: l when 1 a Naphthalenesulfonyl Val titanium, a titanium one naphthalene sulfonyl phenylalanine, l leucine for a naphthalene sulfonyl naphthalene sulfonyl titanium and an isoleucine for a titanium catalyst e.e. values are 52%, 50%, 46% and 56%. on Cyclopentadiene and Methyl Acrylate Diels one. Mder reaction. seldom found good enantioselectivity reported. _1 1994, Boyle et al reported diphenol titanium complex catalyst of the reaction they get the best e.e. value is 26%. Other titanium complexes enantioselectivity even worse than this, ll. sulfonyl amino acid of this study titanium complexes e.e. value reaches 56%. sulfonyl amino acid on the titanium complex to other Diels one. Mder Enantioselective Catalysis of the reaction under study. Referetm ~ lEJc0rey, YMatsumttra.Tea 'aheahm.,�� 991, Wei, 62892EWada.WP,[link widoczny dla zalogowanych], Sm or sister 8aChem.Lea, 19,23453 C,[link widoczny dla zalogowanych], CRSarko, MDiMare.,. Orgthem, 1995.60, l7774KVGothelf, RHHa., e21.KAJorgen ~ en.J.AmChemSoc.1995, J �� 7.44355TAB stare, MALetavic, K0JrIcll, FI Hu Iraq waJOw.0 .. 1 mantis, II796KM, YMotoyama, MTradaJAm .. s. c. .1 State .116,28 l27MiKet, YMotoy, mna.MTerad ~., Chem. $ oc, 1 dragonfly .116,28128 GstyHPo ~ aer, FEydoux.JKkctal ��, 1 dragonfly,, 75419EJCorey, TDRoper,[link widoczny dla zalogowanych], Klshi ~ dra, GSarakJnosTetratuntronLea., 1993,[link widoczny dla zalogowanych],, 839910NFYang.XYWu, YCLin.WLCharttLM�� gYoHuazue, l999, ��9,89 (inChinese) l1JB iv, JSAwalla, ARcmeanick, SSuzuki, PReynolds-Wamhoff, DJWillr Xu,. Am .. Soc., 1961,83,3986 l2TJBoyle,[link widoczny dla zalogowanych], NWFfilexts, JA} en, F Sin g, l., 1994,13,2218 ( Q alum XQ; FANYY)

				fora.pl - załóż własne forum dyskusyjne za darmo Powered by phpBB © 2001, 2002 phpBB Group Avalanche style by What Is Real © 2004