Asymmetric syn-dihydroxylation of γ-substituted (2R)-N-(β,γ-enoyl)bornane-10,2-sultams
摘要:
Various gamma-substituted (2R)-N-( beta,gamma-enoyl)bornane-10,2-sultams have been examined in diastereoselective OsO4 syn-dihydroxylation. In contrast to the C(alpha)-atom, the bornane-10,2-sultam auxiliary exerts a very poor influence on the C(beta)-carbon. Spontaneous stereoselective hydrolysis of the minor diastereoisomer (3S,4S)-5c opens the way to enantiomerically pure building blocks, (C) 2000 Elsevier Science Ltd. All rights reserved.
Asymmetric syn-dihydroxylation of γ-substituted (2R)-N-(β,γ-enoyl)bornane-10,2-sultams
摘要:
Various gamma-substituted (2R)-N-( beta,gamma-enoyl)bornane-10,2-sultams have been examined in diastereoselective OsO4 syn-dihydroxylation. In contrast to the C(alpha)-atom, the bornane-10,2-sultam auxiliary exerts a very poor influence on the C(beta)-carbon. Spontaneous stereoselective hydrolysis of the minor diastereoisomer (3S,4S)-5c opens the way to enantiomerically pure building blocks, (C) 2000 Elsevier Science Ltd. All rights reserved.
new access to enantiopure (Z)-ethylenic pseudopeptides, starting from the chiral pool of amino acids and enantiopure 2-substituted-but-3-enoic acids is proposed and illustrated by the syntheses of the (Z)-ethylenic pseudopeptidic analogs of l-Phe-l-Phe, l-Phe-d-Phe, l-Phe-l-Val, l-Phe-d-Val and racemic (ll,dd) and (ld,dl) (phenyl)Gly-Phe. The key-steps of these syntheses are a ring-closing metathesis
Enantioconservative synthesis and ring closing metathesis of disubstituted dialkenic amides
作者:Hélène Sauriat-Dorizon、François Guibé
DOI:10.1016/s0040-4039(98)01432-4
日期:1998.9
Optically pure disubstituted dialkenic amides 2, which are direct precursors of Z-ethylenic pseudopeptides 1, are readily synthesized and then cyclized to lactams 3 in the presence of Grubbs' ruthenium-based metathesis catalysts with total conservation of enantiomeric purity. (C) 1998 Elsevier Science Lid. All rights reserved.
OPPOLZER, WOLFGANG;MORETTI, ROBERT;THOMI, SILVIA, TETRAHEDRON LETT., 30,(1989) N1, C. 5603-5606