570394-37-5Relevant academic research and scientific papers
Directed hydrogenations and an Ireland-Claisen rearrangement linked to Evans-Tishchenko chemistry: The highly efficient total synthesis of the marine cyclodepsipeptide doliculide
Chen, Tao,Altmann, Karl-Heinz
supporting information, p. 8403 - 8407 (2015/06/02)
Two new convergent total syntheses have been developed for the cytotoxic, actin microfilament-stabilizing marine cyclodepsipeptide doliculide (1). A key strategic element of both routes is the establishment of the central stereogenic center of the characteristic polydeoxypropionate stereotriad by means of a hydroxyl-directed catalytic hydrogenation of a trisubstituted double bond. The requisite olefin substrates were obtained through a modified Suzuki-Miyaura coupling or through Ireland-Claisen rearrangement of a propionate ester, respectively; the latter was the direct result of a highly selective Evans-Tishchenko reduction of a hydroxy ketone that had been obtained in a stereoselective Paterson aldol reaction. Doliculide (1) was finally obtained in a total number of 17 or 15 (14) linear steps, respectively, which represents a substantial improvement over previous syntheses of this highly bioactive natural product.
A scalable route to trisubstituted (E)-vinyl bromides
Cho, Cheon-Gyu,Kim, Won-Suk,Smith III, Amos B.
, p. 3569 - 3572 (2007/10/03)
(Chemical Equation Presented) An effective, readily scalable two-step synthesis of trisubstituted (E)-vinyl bromides involving bromination of α,β-unsaturated lactones followed by hydrolytic fragmentation has been developed. Several trisubstituted (E)-viny
The synthesis of deoxyfusapyrone. 2. Preparation of the bis-trisubstituted olefin fragment and its attachment to the pyrone moiety
Organ, Michael G.,Wang, Junquan
, p. 5568 - 5574 (2007/10/03)
A convergent and modular synthesis has been devised to construct the eight diastereoisomers of deoxyfusapyrone (1). In this paper the synthesis of the complex polyene chain is reported as is its connection to the pyrone moiety that is in the middle of the
Convergent enantioselective synthesis of vinigrol, an architecturally novel diterpenoid with potent platelet aggregation inhibitory and antihypertensive properties. 1. Application of anionic sigmatropy to construction of the octalin substructure
Paquette, Leo A.,Guevel, Ronan,Sakamoto, Shuichi,Kim In Ho,Crawford, Jason
, p. 6096 - 6107 (2007/10/03)
The coupling of building blocks 15 and 36e in the presence of MgBr2·OEt2 at 0 °C proceeds with an exo stereoselectivity (3.2:1) considerably more advantageous for the acquisition of carbinol 37e than in the absence of the additive (exo/endo = 1:5.7). The pivotal transformation that sets all of the relevant stereocenters of the cis-octalin 55 is the oxyanionic-accelerated [3,3]-sigmatropic rearrangement of 37e. A salient feature is the structurally enforced adoption of a boatlike transition state that serves to properly set four vicinal methine hydrogens in an all-cis arrangement. The ensuing conversion of 55 into iodo sulfone 62 has permitted X-ray crystallographic confirmation of all absolute stereochemical assignments since the isopropyl substituent was initially installed enantioselectively via the Evans oxazolidinone protocol. No intramolecular anionic cyclization of 62 to generate the tricyclic framework was seen. This absence of reactivity is attributed to conformational factors that inhibit attainment of the proper SN2 reaction trajectory.
