Intramolecular palladium catalyzed alkoxy carbonylation of 6-hydroxy-1-octenes. Stereoselective synthesis of substituted tetrahydropyrans
摘要:
The reaction of hydroxy alkenes 5, 7, and 8 with CO and MeOH in the presence of PdCl2 and CuCl2 gave tetrahydropyrans 9, 11, and 12, respectively. Yields were dependent upon the configuration of substituents in the hydroxy alkene; in all cases, the tetrahydropyran was produced with 2,6-cis configuration. (C) 1999 Elsevier Science Ltd. All rights reserved.
Total Synthesis of Polycavernoside A, A Lethal Toxin of the Red Alga Polycavernosa tsudai
摘要:
Two approaches to the synthesis of the aglycon 120 of polycavernoside A (1) were developed, only one of which was completed. The successful "second-generation" route assembled the aglycon seco acids 102 and 106 via Nozaki-Hiyama-Kishi coupling of aldehyde 70, prepared from methyl (S)3-hydroxy-2-methylpropionate (72) and (S)-pantolactone (73), with vinyl bromide 71. The latter was obtained from a sequence which commenced from the silyl ether 24 of 3-hydroxypropionaldehyde and entailed cyclization of (Z)-zeta -hydroxy-alpha,beta-unsaturated ester 82. Regioselective Yamaguchi lactonization of trihydroxycarboxylic acids 102 and 106 and subsequent functional-group adjustments led to macrolactone 120, to which the fucopyranosylxylopyranoside moiety was attached. Stille coupling of the glycosidated aglycon 128 with dienylstannane 129 furnished polycavernoside A in a synthesis for which the longest linear sequence was 25 steps. The overall yield to lactone 120 was 4.7%.
Studies toward Luzopeptins: Assembly of the Elusive Serine−PCA Dipeptide
作者:Marco A. Ciufolini、Ning Xi
DOI:10.1021/jo9701952
日期:1997.4.1
BROOKS D. W.; KELLOGG R. P.; COOPER C. S., J. ORG. CHEM., 52,(1987) N 2, 192-196
作者:BROOKS D. W.、 KELLOGG R. P.、 COOPER C. S.
DOI:——
日期:——
Total Synthesis of Polycavernoside A, A Lethal Toxin of the Red Alga <i>Polycavernosa </i><i>t</i><i>sudai</i>
作者:Paul R. Blakemore、Cindy C. Browder、Jian Hong、Christopher M. Lincoln、Pavel A. Nagornyy、Lonnie A. Robarge、Duncan J. Wardrop、James D. White
DOI:10.1021/jo0503862
日期:2005.7.1
Two approaches to the synthesis of the aglycon 120 of polycavernoside A (1) were developed, only one of which was completed. The successful "second-generation" route assembled the aglycon seco acids 102 and 106 via Nozaki-Hiyama-Kishi coupling of aldehyde 70, prepared from methyl (S)3-hydroxy-2-methylpropionate (72) and (S)-pantolactone (73), with vinyl bromide 71. The latter was obtained from a sequence which commenced from the silyl ether 24 of 3-hydroxypropionaldehyde and entailed cyclization of (Z)-zeta -hydroxy-alpha,beta-unsaturated ester 82. Regioselective Yamaguchi lactonization of trihydroxycarboxylic acids 102 and 106 and subsequent functional-group adjustments led to macrolactone 120, to which the fucopyranosylxylopyranoside moiety was attached. Stille coupling of the glycosidated aglycon 128 with dienylstannane 129 furnished polycavernoside A in a synthesis for which the longest linear sequence was 25 steps. The overall yield to lactone 120 was 4.7%.
Intramolecular palladium catalyzed alkoxy carbonylation of 6-hydroxy-1-octenes. Stereoselective synthesis of substituted tetrahydropyrans
作者:James D. White、Jian Hong、Lonnie A. Robarge
DOI:10.1016/s0040-4039(98)02693-8
日期:1999.2
The reaction of hydroxy alkenes 5, 7, and 8 with CO and MeOH in the presence of PdCl2 and CuCl2 gave tetrahydropyrans 9, 11, and 12, respectively. Yields were dependent upon the configuration of substituents in the hydroxy alkene; in all cases, the tetrahydropyran was produced with 2,6-cis configuration. (C) 1999 Elsevier Science Ltd. All rights reserved.