213740-15-9Relevant articles and documents
Cobalt versus Osmium: Control of Both trans and cis Selectivity in Construction of the EFG Rings of Pectenotoxin 4
Roushanbakhti, Ahria,Liu, Yifan,Winship, Paul C. M.,Tucker, Michael J.,Akhtar, Wasim M.,Walter, Daryl S.,Wrigley, Gail,Donohoe, Timothy J.
supporting information, p. 14883 - 14887 (2017/10/24)
Catalytic oxidative cyclisation reactions have been employed for the synthesis of the E and F rings of the complex natural product target pectenotoxin 4. The choice of metal catalyst (cobalt- or osmium-based) allowed for the formation of THF rings with either trans or cis stereoselectivity. Fragment union using a modified Julia reaction then enabled the synthesis of an advanced synthetic intermediate containing the EF and G rings of the target.
Heterocycle synthesis based on allylic alcohol transposition using traceless trapping groups
Xie, Youwei,Floreancig, Paul E.
, p. 4926 - 4929 (2014/05/20)
Allylic alcohols undergo transposition reactions in the presence of Re 2O7 whereby the equilibrium can be dictated by trapping one isomer with a pendent electrophile. Additional ionization can occur when the trapping group is an aldehyde or ketone, thus leading to cyclic oxocarbenium ion formation. Terminating the process through bimolecular nucleophilic addition into the intermediate provides a versatile method for the synthesis of diverse oxygen-containing heterocycles. Understanding the relative rates of the steps in the sequence leads to the design of reactions which create multiple stereocenters with good to excellent levels of control.
Enantioselective intramolecular aldehyde α-alkylation with simple olefins: Direct access to homo-ene products
Comito, Robert J.,Finelli, Fernanda G.,Macmillan, David W. C.
supporting information, p. 9358 - 9361 (2013/07/26)
A highly selective method for the synthesis of asymmetrically substituted carbocycles and heterocycles from unactivated aldehyde-olefin precursors has been achieved via enantioselective SOMO-catalysis. Addition of a catalytically generated enamine radical cation across a pendent olefin serves to establish a general asymmetric strategy toward the production of a wide range of formyl-substituted rings with alkene transposition. Conceptually, this novel mechanism allows direct access to "homo-ene"-type products.
Using heteroaryl-lithium reagents as hydroxycarbonyl anion equivalents in conjugate addition reactions with (S, S)-(+)-pseudoephedrine as chiral auxiliary; Enantioselective synthesis of 3-substituted pyrrolidines
Alonso, Beatriz,Ocejo, Marta,Carrillo, Luisa,Vicario, Jose L.,Reyes, Efraim,Uria, Uxue
, p. 614 - 627 (2013/03/13)
We have developed an efficient protocol for carrying out the stereocontrolled formal conjugate addition of hydroxycarbonyl anion equivalents to α,β-unsaturated carboxylic acid derivatives using (S,S)-(+)-pseudoephedrine as chiral auxiliary, making use of the synthetic equivalence between the heteroaryl moieties and the carboxylate group. This protocol has been applied as key step in the enantioselective synthesis of 3-substituted pyrrolidines in which, after removing the chiral auxiliary, the heteroaryl moiety is converted into a carboxylate group followed by reduction and double nucleophilic displacement. Alternatively, the access to the same type of heterocyclic scaffold but with opposite absolute configuration has also been accomplished by making use of the regio- and diastereoselective conjugate addition of organolithium reagents to α,β,γ,δ-unsaturated amides derived from the same chiral auxiliary followed by chiral auxiliary removal, ozonolysis, and reductive amination/intramolecular nucleophilic displacement sequence.
Studies towards the total synthesis of (-)-callystatin A
Yadav,Yadagiri,Madhuri, Ch.,Sabitha
scheme or table, p. 4269 - 4272 (2011/09/12)
The synthesis of C1-C12 and C13-C 22 fragments of (-)-callystatin A is accomplished employing desymmetrization strategy for the creation of five chiral centres of the polypropionate fragment and application of c
Synthesis of (-)-okilactomycin by a prins-type fragment-assembly strategy
Tenenbaum, Jason M.,Morris, William J.,Custar, Daniel W.,Scheidt, Karl A.
, p. 5892 - 5895 (2011/08/04)
All things converge: A highly convergent synthesis of (-)-okilactomycin utilizes a Prins-type Maitland-Japp cyclization for the fragment assembly of two complex intermediates (see scheme). The synthesis also employs a highly diastereoselective Lewis acid promoted Diels-Alder reaction and an olefin ring-closing metathesis to close a strained 11-membered macrocycle.
Total synthesis of phytophthora mating hormone α1
Wang, Shun-Yi,Song, Ping,Chan, Li-Yan,Loh, Teck-Peng
supporting information; experimental part, p. 5166 - 5169 (2011/02/25)
Total synthesis of Phytophthora mating hormone α1 (1) has been demonstrated. The required stereochemistries (methyl) are achieved by applying CuI-(S)-Tol-BINAP-catalyzed conjugate addition of Grignard reagents to α,β-unsaturated esters.
Total syntheses of amphidinolides B1, B4, G1, H1 and structure revision of amphidinolide H2
Fuerstner, Alois,Bouchez, Laure C.,Morency, Louis,Funel, Jaques-Alexis,Liepins, Vilnis,Poree, Francois-Hugues,Gilmour, Ryan,Laurich, Daniel,Beaufils, Florent,Tamiya, Minoru
experimental part, p. 3983 - 4010 (2009/12/22)
Dinoflagellates of the genus Amphidinium produce a "library" of closely related secondary metabolites of mixed polyketide origin, which are extremely scarce but highly promising owing to the exceptional cytotoxicity against various cancer cell lines. Because of the dense array of sensitive functionalities on their largely conserved macrocyclic frame, however, these amphidinolides of the B, D, G and H types elapsed many previous attempts at their synthesis. Described herein is a robust, convergent and hence general blueprint which allowed not only to conquest five prototype members of these series, but also holds the promise of making "non-natural" analogues available by diverted total synthesis. This notion transpires for a synthesis-driven structure revision of amphidinolide H2. The successful route hinges upon a highly productive Stille-Migita cross-coupling reaction at the congested and chemically labile 1,3-diene site present in all such targets, which required the development of a modified chloride- and fluoride-free protocol. The macrocyclic ring could be formed with high efficiency and selectivity by ring-closing metathesis (RCM) engaging a vinyl epoxide unit as one of the reaction partners. Because of the sensitivity of the targets to oxidizing and reducing conditions as well as to pH changes, the proper adjustment of the protecting group pattern for the peripheral -OH functions also constitutes a critical aspect, which has to converge to silyl groups only once the diene is in place. Tris(dime-thylamino)sulfomum difluorotrimethyl-silicate (TASF) turned out to be a sufficiently mild fluoride source to allow for the final deprotection without damaging the precious macrolides.
Efficient and stereoselective synthesis of yellow scale pheromone via alkyne haloboration, Zr-catalyzed asymmetric carboalumination of alkenes (ZACA reaction), and Pd-catalyzed tandem negishi coupling
Xu, Zhaoqing,Negishi, Ei-Ichi
supporting information; experimental part, p. 4311 - 4314 (2009/06/06)
(Chemical Equation Presented) A Pd-catalyzed reaction of allylzincs with the 1-octyne bromoboration product gives the desired allyl-alkenyl coupling products in good yields except with H2C=CHCH2ZnBr. This reaction is suitable for con
Zirconium-catalyzed asymmetric carboalumination of alkenes: ZACA-lipase-catalyzed acetylation synergy
Huang, Zhihong,Tan, Ze,Novak, Tibor,Zhu, Gangguo,Negishi, Ei-Ichi
, p. 539 - 545 (2008/02/08)
ZACA-lipase-catalyzed acetylation tandem reactions provide highly efficient and selective routes to either (R)- or (S)-2-methyl-1-alkanols, making, for the first time, the ZACA-based asymmetric synthesis of 2-methyl-1-alkanols widely applicable and satisfactory.
