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Chung-Yeh Wu et al.
Nature, 517(7535), 449-454 (2015-01-23)
Low-valent late transition-metal catalysis has become indispensable to chemical synthesis, but homogeneous high-valent transition-metal catalysis is underdeveloped, mainly owing to the reactivity of high-valent transition-metal complexes and the challenges associated with synthesizing them. Here we report a carbon-carbon bond cleavage
Takuya Hashimoto et al.
Nature chemistry, 5(3), 240-244 (2013-02-21)
Allenes are molecules based on three carbons connected by two cumulated carbon-carbon double bonds. Given their axially chiral nature and unique reactivity, substituted allenes have a variety of applications in organic chemistry as key synthetic intermediates and directly as part
Francois Grillet et al.
The Journal of organic chemistry, 78(8), 3737-3754 (2013-03-15)
A transfer of chirality in an intramolecular Rh(I)-catalyzed allenic Pauson-Khand reaction (APKR) to access tetrahydroazulenones, tetrahydrocyclopenta[c]azepinones and dihydrocyclopenta[c]oxepinones enantioselectively (22-99% ee) is described. The substitution pattern of the allene affected the transfer of chiral information. Complete transfer of chirality was
David Tejedor et al.
Chemical Society reviews, 42(2), 458-471 (2012-10-05)
The propargyl Claisen rearrangement is a known protocol to gain access to functionalized allenes through the [3,3]-sigmatropic transformation of propargyl vinyl ethers. The correct use of appropriate propargyl vinyl ethers as starting materials coupled with suitable reaction conditions can aid
Hussein H Mustafa et al.
Chemical communications (Cambridge, England), 49(25), 2497-2499 (2013-02-20)
Both diastereomers of the tris-allene, cyclododeca-1,2,5,6,9,10-hexaene have been obtained using a triple cyclopropylidene-allene rearrangement. On the NMR timescale, one has D3 symmetry, and is the smallest hydrocarbon synthesised to have this symmetry, and the second has C2 symmetry.
Zhanjie Li et al.
Journal of the American Chemical Society, 134(37), 15497-15504 (2012-08-29)
Rhodium-catalyzed reactions of tertiary propargylic alcohols with methyl aryl- and styryldiazoacetates result in tandem reactions, consisting of oxonium ylide formation followed by [2,3]-sigmatropic rearrangement. This process competes favorably with the standard O-H insertion reaction of carbenoids. The resulting allenes are
Benito Alcaide et al.
Chemical communications (Cambridge, England), 49(13), 1282-1284 (2013-01-09)
The divergent gold-catalysed reactivity (C(sp(2))-H versus C(sp(3))-H) of aryloxy-tethered allenes has been uncovered.
Miao Hong et al.
Macromolecular rapid communications, 33(11), 998-1002 (2012-03-14)
Allene groups are first employed as the reactive moiety in the simple and efficient synthesis of well-defined functional polyethylene. By copolymerization of ethylene with allene group substituted norbornene, the allene group is successfully introduced into the polyethylene with a high
Bonnie S Watson et al.
Plant physiology, 167(4), 1699-1716 (2015-02-11)
Integrated metabolomics and transcriptomics of Medicago truncatula seedling border cells and root tips revealed substantial metabolic differences between these distinct and spatially segregated root regions. Large differential increases in oxylipin-pathway lipoxygenases and auxin-responsive transcript levels in border cells corresponded to
Liming Wang et al.
The Journal of clinical investigation, 125(5), 1913-1926 (2015-04-07)
Familial forms of focal segmental glomerulosclerosis (FSGS) have been linked to gain-of-function mutations in the gene encoding the transient receptor potential channel C6 (TRPC6). GPCRs coupled to Gq signaling activate TRPC6, suggesting that Gq-dependent TRPC6 activation underlies glomerular diseases. Here
Nathalie Tijet et al.
Prostaglandins & other lipid mediators, 68-69, 423-431 (2002-11-16)
Allene oxides are unstable epoxides formed by the enzymatic dehydration of the lipoxygenase products of polyunsaturated fatty acids. The allene oxide synthases are of two structurally-unrelated types. In plants, a subfamily of cytochromes P450, designated as CYP74A, use the hydroperoxides
Catalytic asymmetric allenylation of malonates with the generation of central chirality.
Qiankun Li et al.
Angewandte Chemie (International ed. in English), 51(47), 11783-11786 (2012-10-12)
Wangqing Kong et al.
Organic & biomolecular chemistry, 10(10), 2164-2173 (2012-02-03)
A detailed study on the scope of the efficient PtCl(2)-catalyzed synthesis of carbazoles from 1-(indol-2-yl)-2,3-allenols is described. Through isotopic labeling experiments, it is confirmed that the reaction proceeds through a unique metal carbene intermediate, which undergoes subsequent highly selective 1,2-hydrogen
Cheng-Kui Pei et al.
Organic & biomolecular chemistry, 10(22), 4355-4361 (2012-05-05)
β-Isocupreidine (β-ICD) catalyzed asymmetric [4 + 2] cycloaddition of β,γ-unsaturated α-ketoesters with allenic esters afforded ester-substituted functionalized dihydropyran derivatives in high yields along with high enantioselectivities under mild conditions.
Ming Chen et al.
Organic letters, 15(7), 1662-1665 (2013-03-29)
The enantioselective hydroboration of racemic allenylsilane (±)-4 with ((d)Ipc)2BH proceeds via enantiodivergent pathways to give vinylborane 11 and crotylborane intermediate (S)-E-5. Subsequent crotylboration of aldehyde substrates with (S)-E-5 at -78 °C provides (E)-δ-silyl-anti-homoallylic alcohols in 71-89% yield and with 93-96%
Richard B Thompson et al.
Proceedings of the National Academy of Sciences of the United States of America, 112(5), 1565-1570 (2015-01-22)
Accumulation of protein- and lipid-containing deposits external to the retinal pigment epithelium (RPE) is common in the aging eye, and has long been viewed as the hallmark of age-related macular degeneration (AMD). The cause for the accumulation and retention of
Chenggang Liu et al.
Plant physiology, 165(4), 1424-1439 (2014-06-21)
In Arabidopsis (Arabidopsis thaliana), the major MYB protein regulating proanthocyanidin (PA) biosynthesis is TT2, named for the transparent testa phenotype of tt2 mutant seeds that lack PAs in their coats. In contrast, the MYB5 transcription factor mainly regulates seed mucilage
Kenta Yamamoto et al.
Proceedings of the National Academy of Sciences of the United States of America, 112(19), 6152-6157 (2015-04-29)
Osteoblasts produce calcified bone matrix and contribute to bone formation and remodeling. In this study, we established a procedure to directly convert human fibroblasts into osteoblasts by transducing some defined factors and culturing in osteogenic medium. Osteoblast-specific transcription factors, Runt-related
Jakub T Flasz et al.
Organic letters, 14(12), 3024-3027 (2012-06-01)
A new formal total synthesis of (-)-echinosporin has been developed based upon the Padwa [3 + 2]-cycloadditive elimination reaction of allenylsulfone 4 with the D-glucose-derived enone 14 which provides cycloadduct 12.
Stefano Protti et al.
Angewandte Chemie (International ed. in English), 51(34), 8577-8580 (2012-07-19)
Doubly radical: A novel entry to α,n-didehydrotoluene (DHT) diradicals is disclosed and proceeds through the photochemical activation of (chlorobenzyl)trimethylsilanes with chloride loss and elimination of the SiMe(3) (+) group. The products formed in solution are indicative of the intermediacy of
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