Synthetic studies on cyathin diterpenes - Total synthesis of (±)-allocyathin B3

2004 ◽  
Vol 82 (2) ◽  
pp. 254-267 ◽  
Author(s):  
Dale E Ward ◽  
Yuanzhu Gai ◽  
Qi Qiao ◽  
Jianheng Shen
Keyword(s):  
Total Synthesis ◽  
Ring System ◽  
Radical Cyclization ◽  
Isopropyl Group ◽  
Hydroxymethyl Group ◽  
Relative Stereochemistry ◽  
Synthetic Studies ◽  
Vinyl Triflate

The synthesis of racemic allocyathin B3 from an advanced intermediate possessing the ring system and relative stereochemistry but lacking the isopropyl and hydroxymethyl groups is reported. The isopropyl group was introduced by radical cyclization of a methyl propargyl acetal of an α-bromoketone and the hydroxymethyl group was generated by Pd-catalyzed carbonylation of a vinyl triflate. The route provides functionalized intermediates that could allow access to more complex members of the cyathin family of diterpenes. Several modifications and improvements to the procedures previously described for the synthesis of the advanced intermediate have been achieved.Key words: cyathin diterpenes, cyathanes, allocyathin B3.

Synthetic studies on virantmycin. 1. Total synthesis of (±)-virantmycin and determination of its relative stereochemistry

Tetrahedron ◽  
1996 ◽  
Vol 52 (32) ◽  
pp. 10609-10630 ◽  
Author(s):  
Yoshiki Morimoto ◽  
Fuyuhiko Matsuda ◽  
Haruhisa Shirahama
Keyword(s):  
Total Synthesis ◽  
Relative Stereochemistry ◽  
Synthetic Studies

Concise Total Synthesis of Curvulone B

Synlett ◽  
2020 ◽  
Author(s):  
Debendra K. Mohapatra ◽  
Shivalal Banoth ◽  
Utkal Mani Choudhury ◽  
Kanakaraju Marumudi ◽  
Ajit C. Kunwar
Keyword(s):  
Total Synthesis ◽  
Stereoselective Synthesis ◽  
Ring System ◽  
Bond Forming ◽  
Cross Metathesis ◽  
Bond Forming Reactions ◽  
Key Steps

AbstractA concise and convergent stereoselective synthesis of curvulone B is described. The synthesis utilized a tandem isomerization followed by C–O and C–C bond-forming reactions following Mukaiyama-type aldol conditions for the construction of the trans-2,6-disubstituted dihydropyran ring system as the key steps. Other important features of this synthesis are a cross-metathesis, epimerization, and Friedel–Crafts acylation.

ChemInform Abstract: TOTAL SYNTHESIS OF THE 6-SILASTEROID RING SYSTEM

1975 ◽  
Vol 6 (52) ◽  
pp. no-no
Author(s):  
S. BARCZA ◽  
C. W. HOFFMAN
Keyword(s):  
Total Synthesis ◽  
Ring System

scholarly journals Studies on the Enantioselective Synthesis of E-Ethylidene-bearing Spiro[indolizidine-1,3′-oxindole] Alkaloids

Molecules ◽  
2021 ◽  
Vol 26 (2) ◽  
pp. 428
Author(s):  
Nihan Yayik ◽  
Maria Pérez ◽  
Elies Molins ◽  
Joan Bosch ◽  
Mercedes Amat
Keyword(s):  
Ring System ◽  
Enantioselective Synthesis ◽  
Synthetic Route ◽  
Hydroxymethyl Group ◽  
Hydride Reduction ◽  
Lactam Carbonyl ◽  
Key Steps ◽  
Oxindole Alkaloids

A synthetic route for the enantioselective construction of the tetracyclic spiro[indolizidine-1,3′-oxindole] framework present in a large number of oxindole alkaloids, with a cis H-3/H-15 stereochemistry, a functionalized two-carbon substituent at C-15, and an E-ethylidene substituent at C-20, is reported. The key steps of the synthesis are the generation of the tetracyclic spirooxindole ring system by stereoselective spirocyclization from a tryptophanol-derived oxazolopiperidone lactam, the removal of the hydroxymethyl group, and the stereoselective introduction of the E-ethylidene substituent by acetylation at the α-position of the lactam carbonyl, followed by hydride reduction and elimination. Following this route, the 21-oxo derivative of the enantiomer of the alkaloid 7(S)-geissoschizol oxindole has been prepared.

New Approach to the Steroid BCD-Ring System Using Tandem Radical Cyclization

1997 ◽  
Vol 62 (7) ◽  
pp. 1912-1913 ◽  
Author(s):  
Takashi Takahashi ◽  
Satoshi Tomida ◽  
Yasuharu Sakamoto ◽  
Haruo Yamada
Keyword(s):  
Ring System ◽  
Radical Cyclization ◽  
New Approach

scholarly journals Short, enantioselective, gram-scale synthesis of (−)-zephyranthine

2021 ◽  
Author(s):  
Yuxiang Zhao ◽  
Yanren Zhu ◽  
Guolan Ma ◽  
Qi Wei ◽  
Shaoxiong Yang ◽  
...  
Keyword(s):  
Total Synthesis ◽  
Functional Group ◽  
Ring System ◽  
System Construction ◽  
Synthesis Design

A reasonable synthesis design by strategically integrating functional group manipulation into the ring system construction resulted in a short, enantioselective, gram-scale total synthesis of (−)-zephyranthine.

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