Enantio- and Diastereoselective Catalysis of Addition Reaction of Allylic Silanes and Stannanes to Glyoxylates by Binaphthol-derived Titanium Complex
Chiral titanium complex (1), prepared in situ from optically pure binaphthol and diisopropoxytitanium dihalide in the presence of molecular sieves, is shown to catalyze the addition reactions of crotylsilanes and -stannanes to glyoxylates to afford (syn)-α-hydroxy-β-methyl esters in highly scalemic forms with high diastereoselectivity.Key Words: Asymmetric catalysis; Enantiocontrol; Diastereocontrol; Allylic silane; Allylic stannane; Carbonyl-addition reaction; Carbonyl-enereaction; Glyoxylate; Binaphthol-derived titanium dihalide; Chiral titanium complex
STUDIES ON STRUCTURALLY SIMPLE α,β-BUTENOLIDES. III. BEHAVIOUR OF (-)-(S)-δ-HETEROSUBSTITUTED γ-METHYL-α,β-BUTENOLIDES TOWARDS NUCLEOPHILES. PROTOANEMONIN AS INTERMEDIATE IN AN ELIMINATION-ADDITION MECHANISM.
The reactivity of the title compounds with different nucleophiles has been checked and it was shown that products from reaction with sodium phenylthiolate result from an elimination-addition process in which protoanemonin is the key intermediate.The synthesis of (-)-(R)-β-angelica lactone is reported for the first time.
Camps, P.,Cardellach, J.,Corbera, J.,Font, J.,Ortuno, R. M.,Ponsati, O.
p. 395 - 400
(2007/10/02)
Ortho Ester Claisen Rearrangements Using Trimethyl Methoxyorthoacetate
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Daub, G. William,Teramura, Douglas H.,Bryant, Kevin E.,Bruch, Mark T.
p. 1485 - 1486
(2007/10/02)
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