146436-22-8Relevant academic research and scientific papers
Enantioselective synthesis of (-)-terpestacin and structural revision of siccanol using catalytic stereoselective fragment couplings and macrocyclizations
Chan, Johann,Jamison, Timothy F.
, p. 10682 - 10691 (2004)
(-)-Terpestacin (1, naturally occurring enantiomer) and (+)-11-epi-terpestacin (2) were prepared using catalyst-controlled, stereoselective, intermolecular reductive coupling reactions of alkyne 9 and aldehyde 10, affording allylic alcohols 42 or 11-epi-42 in a 3:1 ratio (or 1:3 depending on the enantiomer of ligand 41a used). These stereoselective fragment couplings were instrumental in confirming that "siccanol" is not 11-epi-terpestacin but, in fact, is (-)-terpestacin itself. Several intramolecular alkyne-aldehyde reductive coupling approaches to 1 and 2 were also investigated and are discussed herein.
Two new diketopiperazines and a new glucosyl sesterterpene from Alternaria alternata, an endophytic fungi from Ceratostigma griffithii
Guo, Da-Le,Zhao, Min,Xiao, Shi-Ji,Xia, Bing,Wan, Bo,Gu, Yu-Cheng,Ding, Li-Sheng,Zhou, Yan
, p. 260 - 264 (2015)
Two diketopiperazine derivatives, altenarizines A (1) and B (2), and a new glucosyl sesterterpene, 24-α-d-glucosyl-(-)-terpestacin (3), together with two known phytotoxic sesterterpenes, (-)-terpestacin (4) and fusaproliferin (5), were isolated from the fermentation broth of an endophytic fungus Alternaria alternata, which was obtained from the fresh root of Ceratostigma griffithii. Structures of all the isolates were identified by spectroscopic data.
Enantioselective synthesis of (-)-terpestacin and (-)-fusaproliferin: Clarification of optical rotational measurements and absolute configurational assignments establishes a homochiral structural series
Myers, Andrew G.,Siu, Michael,Ren, Feng
, p. 4230 - 4232 (2002)
An enantioselective synthesis of the syncytium formation inhibitor (-)-terpestacin (1, 19 steps, 5.8% yield from the allylation product of (R,R)-pseudoephedrine propionamide, 3) and the fungal metabolite (-)-fusaproliferin (2, 21 steps, 5.3% yield from 3) in their natural configurations is described. The route employs a series of stereoselective enolate alkylation reactions to establish the initial stereogenic center, set the quaternary carbon configuration, close the 15-membered ring, and introduce the side-chain residue with proper stereocontrol. Careful analysis of our synthetic materials alongside natural samples has revealed that several errors were made in the earlier measurements of optical rotation or in the absolute stereochemical assignments of these natural products. Clarifying all discrepancies, we show here that natural terpestacin (1) is levorotatory, not dextrorotatory as originally described, but was correctly assigned as the (1S,11S,15R,23S)-enantiomer. Fusaproliferin (2) is levorotatory, as reported, but is in fact the (1S,11S,15R,23S)-enantiomer and not the antipodal configuration originally assigned. Copyright
A convergent stereocontrolled total synthesis of (-)-terpestacin
Jin, Yehua,Qiu, Fayang G.
, p. 5452 - 5455 (2012/08/08)
A stereocontrolled total synthesis of (-)-terpestacin has been achieved starting from (R)-(-)-carvone as a chiral pool and (E,E)-farnesol via a highly convergent approach. Thus, (R)-(-)-carvone was transformed into the cyclopentanone segment through a series of high yielding operations with the proper setup of all the stereochemical centers while (E,E)-farnesol was converted into the other requisite building block via a series of high yielding reactions. The cyclopentanone intermediate was both selectively enolized and alkylated at room temperature to yield the desired coupling product, which provided the natural product upon further transformations.
Cyclic 1,2-Diketones as core building blocks: A strategy for the total synthesis of (-)-terpestacin
Trost, Barry M.,Dong, Guangbin,Vance, Jennifer A.
supporting information; experimental part, p. 6265 - 6277 (2010/07/20)
We report a full account of our work towards the total synthesis of (-)-terpestacin (1), a sesterterpene originally isolated from fungal strain Arthrinium sp. FA1744. Its promising anti-HIV and anti-cancer activity, as well as its novel structure, make terpestacin an attractive synthetic target. A strategy based on the unique reactivity of cyclic 1,2-diketones (diosphenols) was developed and total synthesis of 1 was achieved in 20 steps, in the longest linear sequence, from commercially available 2-hydroxy-3-methyl-2-cyclopenten-1- one. The key feature of our synthesis is the double usage of a "Pd AAA-Claisen" protocol (AAA = asymmetric allylic alkylation), first in the early stages to generate the C1 quaternary center and then in the late stages to install the side chain. In addition, a rather unusual ene-1,2-dione moiety was synthesized and utilized as an excellent Michael acceptor to attach the C15 substituent. Several possible routes towards the total synthesis have been examined and carefully evaluated. During our exploration many interesting chemoselectivity issues have been addressed, such as a highly selective ring-closing metathesis and a challenging oxidation of a disubstituted olefin in the presence of three trisubstiuted ones.
A diosphenol-based strategy for the total synthesis of (-)-terpestacin
Trost, Barry M.,Dong, Guangbin,Vance, Jennifer A.
, p. 4540 - 4541 (2007/10/03)
A novel diosphenol-based strategy has been developed for the enantioselective synthesis of (-)-terpestacin by multiple usage of the α-diketone functionality, first in the "Pd AAA-Claisen rearrangement" protocol, and second by the employment of its oxidized form, the ene-1,2-dione, as an excellent Michael acceptor. This synthesis demonstrates that the sequence of O-allylation-Claisen rearrangement provides a chemo- and regioselective enolate allylation, which can be performed asymmetrically with respect to the enolate or allyl fragment or both. In addition, many interesting chemoselectivity issues, including a highly selective RCM and a dihydroxylation, have been addressed. Overall, this synthesis was accomplished in 20 longest linear steps (24 total steps) from the inexpensive and commercially available 3-methyl-1,2-cyclopentanedione. Copyright
