19945-61-0Relevant articles and documents
Olefination of activated halides and mesylates using arsonium ylides
Seyer, Andre,Alcaraz, Lilian,Mioskowski
, p. 7871 - 7874 (1997)
Alkyltriphenylarsonium ylides react with activated primary halides and mesylates to afford olefins in good yields and with high E-selectivity.
Z-Selective Cross-Metathesis and Homodimerization of 3E-1,3-Dienes: Reaction Optimization, Computational Analysis, and Synthetic Applications
Luo, Shao-Xiong,Cannon, Jeffrey S.,Taylor, Buck L. H.,Engle, Keary M.,Houk,Grubbs, Robert H.
, p. 14039 - 14046 (2016)
Olefin metathesis reactions with 3E-1,3-dienes using Z-selective cyclometalated ruthenium benzylidene catalysts are described. In particular, a procedure for employing 3E-1,3-dienes in Z-selective homodimerization and cross-metathesis with terminal alkenes is detailed. The reaction takes advantage of the pronounced chemoselectivity of a recently reported ruthenium-based catalyst containing a cyclometalated NHC ligand for terminal alkenes in the presence of internal E-alkenes. A wide array of commonly encountered functional groups can be tolerated, and only a small excess (1.5 equiv) of the diene coupling partner is required to achieve high yields of the desired internal E,Z-diene cross-metathesis product. Computational studies have been performed to elucidate the reaction mechanism. The computations are consistent with a diene-first pathway. The reaction can be used to quickly assemble structurally complex targets. The power of this cross-metathesis reaction is demonstrated by the concise syntheses of two insect pheromones.
Biosynthesis of C11 and C16 homoterpenes in higher plants; stereo- chemistry of the C-C-bond cleavage reaction
Boland, Wilhelm,Gaebler, Andreas,Gilbert, Matthias,Feng, Zhuofu
, p. 14725 - 14736 (1998)
In higher plants the C11 homoterpene 4,8-dimethylnona-1,3,7-triene (1) originates from oxidative degradation of nerolidol (3) or geranylacetone (4). The geometry of the transition state of bond cleavage has been shown to be syn-periplanar, for both 3 and 4 by application of chirally labelled, deuterated precursors to flowers of Magnolia liliiflora nigra or leaves of the Lima bean Phaseolus lunatus. The synthesis of the deuterated, chiral metabolic probes 3 and 8 from nor-farnesene (5), via the enantiomeric epoxides (2S,3R)-6 and ent-6, is described.
Herbivore-induced and floral homoterpene volatiles are biosynthesized by a single P450 enzyme (CYP82G1) in Arabidopsis
Lee, Sungbeom,Badieyan, Somayesadat,Bevan, David R.,Herde, Marco,Gatz, Christiane,Tholl, Dorothea
, p. 21205 - 21210 (2010)
Terpene volatiles play important roles in plant-organism interactions as attractants of pollinators or as defense compounds against herbivores. Among the most common plant volatiles are homoterpenes, which are often emitted from night-scented flowers and from aerial tissues upon herbivore attack. Homoterpene volatiles released from herbivore-damaged tissue are thought to contribute to indirect plant defense by attracting natural enemies of pests. Moreover, homoterpenes have been demonstrated to induce defensive responses in plant-plant interaction. Although early steps in the biosynthesis of homoterpenes have been elucidated, the identity of the enzyme responsible for the direct formation of these volatiles has remained unknown. Here, we demonstrate that CYP82G1 (At3g25180), a cytochrome P450 monooxygenase of the Arabidopsis CYP82 family, is responsible for the breakdown of the C20-precursor (E,E)-geranyllinalool to the insect-induced C16-homoterpene (E,E)-4,8,12-trimethyltrideca-1,3,7,11-tetraene (TMTT). Recombinant CYP82G1 shows narrow substrate specificity for (E,E)- geranyllinalool and its C 15-analog (E)-nerolidol, which is converted to the respective C 11-homoterpene (E)-4,8-dimethyl-1,3,7-nonatriene (DMNT). Homology-based modeling and substrate docking support an oxidative bond cleavage of the alcohol substrate via syn-elimination of the polar head, together with an allylic C-5 hydrogen atom. CYP82G1 is constitutively expressed in Arabidopsis stems and inflorescences and shows highly coordinated herbivoreinduced expression with geranyllinalool synthase in leaves depending on the F-box protein COI-1. CYP82G1 represents a unique characterized enzyme in the plant CYP82 family with a function as a DMNT/TMTT homoterpene synthase.
Amides as bioisosteres of triazole-based geranylgeranyl diphosphate synthase inhibitors
Goetz, Daniel B.,Holstein, Sarah A.,Varney, Michelle L.,Wiemer, David F.
, (2020/07/10)
Geranylgeranyl diphosphate synthase (GGDPS) inhibitors are of potential therapeutic interest as a consequence of their activity against the bone marrow cancer multiple myeloma. A series of bisphosphonates linked to an isoprenoid tail through an amide linkage has been prepared and tested for the ability to inhibit GGDPS in enzyme and cell-based assays. The amides were designed as analogues to triazole-based GGDPS inhibitors. Several of the new compounds show GGDPS inhibitory activity in both enzyme and cell assays, with potency dependent on chain length and olefin stereochemistry.
Highly Selective and Catalytic Generation of Acyclic Quaternary Carbon Stereocenters via Functionalization of 1,3-Dienes with CO2
Chen, Xiao-Wang,Zhu, Lei,Gui, Yong-Yuan,Jing, Ke,Jiang, Yuan-Xu,Bo, Zhi-Yu,Lan, Yu,Li, Jing,Yu, Da-Gang
, p. 18825 - 18835 (2019/11/28)
The catalytic asymmetric functionalization of readily available 1,3-dienes is highly important, but current examples are mostly limited to the construction of tertiary chiral centers. The asymmetric generation of acyclic products containing all-carbon quaternary stereocenters from substituted 1,3-dienes represents a more challenging, but highly desirable, synthetic process for which there are very few examples. Herein, we report the highly selective copper-catalyzed generation of chiral all-carbon acyclic quaternary stereocenters via functionalization of 1,3-dienes with CO2. A variety of readily available 1,1-disubstituted 1,3-dienes, as well as a 1,3,5-triene, undergo reductive hydroxymethylation with high chemo-, regio-, E/Z-, and enantioselectivities. The reported method features good functional group tolerance, is readily scaled up to at least 5 mmol of starting diene, and generates chiral products that are useful building blocks for further derivatization. Systemic mechanistic investigations using density functional theory calculations were performed and provided the first theoretical investigation for an asymmetric transformation involving CO2. These computational results indicate that the 1,2-hydrocupration of 1,3-diene proceeds with high π-facial selectivity to generate an (S)-allylcopper intermediate, which further induces the chirality of the quaternary carbon center in the final product. The 1,4-addition of an internal allylcopper complex, which differs from previous reports involving terminal allylmetallic intermediates, to CO2 kinetically determines the E/Z- and regioselectivity. The rapid reduction of a copper carboxylate intermediate to the corresponding silyl-ether in the presence of Me(MeO)2SiH provides the exergonic impetus and leads to chemoselective hydroxymethylation rather than carboxylation. These results provide new insights for guiding further development of asymmetric C-C bond formations with CO2
Organoselenium-Catalyzed Regioselective C?H Pyridination of 1,3-Dienes and Alkenes
Liao, Lihao,Guo, Ruizhi,Zhao, Xiaodan
supporting information, p. 3201 - 3205 (2017/03/17)
An efficient approach for organoselenium-catalyzed regioselective C?H pyridination of 1,3-dienes to form pyridinium salts has been developed. This method was also successfully applied to direct C?H pyridination of alkenes. Fluoropyridinium reagents, or initially loaded pyridine derivatives, acted as pyridine sources in the pyridination reactions. The obtained pyridinium salts could be further converted under different conditions. This work is the first example of catalytic C-2 direct C?H functionalization of 1,3-dienes and the first case of organoselenium-catalyzed C?H pyridination.
Catalytic enantioselective 1,2-diboration of 1,3-dienes: Versatile reagents for stereoselective allylation
Kliman, Laura T.,Mlynarski, Scott N.,Ferris, Grace E.,Morken, James P.
supporting information; scheme or table, p. 521 - 524 (2012/03/11)
More with boron: The development of catalytic enantioselective 1,2-diboration of 1,3-dienes enables a new strategy for enantioselective carbonyl allylation reactions (see scheme). These reactions occur with outstanding levels of stereoselection and can be applied to both monosubstituted and 1,1-disubstituted dienes. The carbonyl allylation reactions provide enantiomerically enriched functionalized homoallylic alcohol products. Copyright
A direct synthesis of functionalized styrenes and terminal 1,3-dienes via aqueous Wittig chemistry with formalin
Das, Priyabrata,McLeod, David,McNulty, James
experimental part, p. 199 - 201 (2011/02/26)
A direct synthesis of functionalized styrenes including synthetically valuable styryl halides and terminal 1,3-dienes is reported directly from benzylic and allylic alcohols and aqueous formalin involving microwave assisted phosphonium salt formation and Wittig olefination under mildly basic conditions.
Efficient one-to-one coupling of easily available 1,3-dienes with carbon dioxide
Takaya, Jun,Sasano, Kota,Iwasawa, Nobuharu
supporting information; experimental part, p. 1698 - 1701 (2011/05/04)
An efficient one-to-one coupling reaction of atmospheric pressure carbon dioxide with 1,3-dienes is realized for the first time through PSiP-pincer type palladium-catalyzed hydrocarboxylation. The reaction is applicable to various 1,3-dienes including easily available chemical feedstock such as 1,3-butadiene and isoprene. This protocol affords a highly useful method for the synthesis of β,γ-unsaturated carboxylic acid derivatives from CO2.
