1777-33-9Relevant academic research and scientific papers
Synthesis and Olfactory Properties of a 6′-Silasubstituted “Spiro[4.5]-δ-Damascone”
Lovchik, Martin A.,Kraft, Philip
, p. 4590 - 4596 (2017)
The silicon analogue of the potent spirocyclic δ-damascone odorant 6 was synthesized from allyltrichlorosilane (15) and but-2-en-1-ol (16). The latter was transformed to 3-methylpen-4-enenitrile (11) by Saucy–Marbet reaction with ethoxyethane and subsequent treatment with HONH2?HCl. The resulting γ,δ-unsaturated nitrile 11 was silylated with 1-allyl-1-chlorosilolane (14), which was prepared from allyltrichlorosilane (15) and the bis-Grignard reagent of 1,4-dichlorobutane. Metathetic ring closure employing the Grubbs I catalyst, followed by DIBAL reduction with non-aqueous work up, Grignard reaction with prop-1-en-1-ylmagnesium bromide, and Attenburrow MnO2 oxidation concluded the synthesis. The target compound was found to be olfactorily related to the spiro[4.5]-δ-damascone lead, but approximately 900 times weaker. In a type of enol Brook rearrangement, it thermally decomposes however to 3,6-dihydro-2H-1,2-oxasilocine (20), which surprisingly is a damascone odorant as well; although, 12 000 times weaker.
A Formal Enantiospecific Synthesis of 7,20-Diisocyanoadociane
Roosen, Philipp C.,Vanderwal, Christopher D.
, p. 7180 - 7183 (2016)
7,20-Diisocyanoadociane (DICA) is a potent antimalarial isocyanoterpene endowed with a fascinating tetracyclic structure composed of fused chair cyclohexanes. We report a highly stereocontrolled synthesis of a late-stage intermediate, the “Corey dione”, from which DICA has been made previously. This formal synthesis features a rapid buildup of much of the complexity of the target through a sequence of enone tandem vicinal difunctionalization, Friedel–Crafts cyclodehydration, and sequential stereocontrolled reductions. Most importantly, this success establishes the broader feasibility of our previously developed general synthesis approach to the isocyanoterpene family and provides a blueprint for a very direct synthesis of DICA and related natural products.
APPROACHES TO THE SYNTHESIS OF ASPIDOSPERMA ALKALOIDS. PART I. PRELIMINARY STUDIES IN THE VINCADIFFORMINE GROUP.
Costello, Gerard,Saxton, J. Edwin
, p. 6047 - 6069 (1986)
As a preface to work leading to the total synthesis of 18,19-dehydrotabersonine, described in the following paper, some older work on the synthesis of (+/-)-3-oxo-20-desethyl-20-allylvincadifformine, its C-20 epimer, and (+/-)-3-oxo-19-vinylvincadifformine is reported.Attempts to convert these compounds, by appropriate manipulation of the isolated double bond, into a wide range of anilinoacrylate alkaloids, e.g. minovincine, tuboxenine, and pseudokopsinine, are described.Methods for the functionalisation of the double bond at an earlier stage in the synthesis, e.g. using 3,18-dioxo-1-demethylvincatine, have also been investigated.
COMPOUNDS THAT INHIBIT MCL-1 PROTEIN
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Page/Page column 1197, (2017/09/15)
Provided herein are myeloid cell leukemia 1 protein (Mcl-1) inhibitors, methods of their preparation, related pharmaceutical compositions, and methods of using the same. For example, provided herein are compounds of Formula I, and pharmaceutically acceptable salts thereof and pharmaceutical compositions containing the compounds. The compounds and compositions provided herein may be used, for example, in the treatment of diseases or conditions, such as cancer.
Photocatalytic One-Pot Synthesis of Homoallyl Ketones via a Norrish Type i Reaction of Cyclopentanones
Okada, Megumi,Yamada, Keiichi,Fukuyama, Takahide,Ravelli, Davide,Fagnoni, Maurizio,Ryu, Ilhyong
, p. 9365 - 9369 (2015/09/28)
A photocatalytic synthesis of homoallyl ketones was achieved via a one-pot procedure starting from a Norrish Type I reaction of cyclopentanones, followed by a decatungstate-catalyzed hydroacylation of electron-deficient olefins by the resulting 4-pentenals. The site-selective formyl H-abstraction in the second step can be explained by radical polar effects in the transition state.
Tandem Pd(II)-catalyzed vinyl ether exchange-claisen rearrangement as a facile approach to γ,δ-unsaturated aldehydes
Wei, Xudong,Lorenz, Jon C.,Kapadia, Suresh,Saha, Anjan,Haddad, Nizar,Busacca, Carl A.,Senanayake, Chris H.
, p. 4250 - 4253 (2008/02/04)
(Chemical Equation Presented) A sequential allyl vinyl ether formation-Claisen rearrangement process catalyzed by a palladium(II)- phenanthroline complex is reported. The effects of allylic alcohol structure, type of vinylating agent, and palladium catalysts are discussed. This method provides a convenient approach to γ,δ unsaturated aldehydes under mild conditions that avoid the use of toxic Hg(II) catalysts. The new methodology has been successfully demonstrated on the kilogram scale.
Gas-phase chemistry of dihydromyrcenol with ozone and OH radical: Rate constants and products
Forester, Crystal D.,Ham, Jason E.,Wells
, p. 451 - 463 (2008/02/09)
A bimolecular rate constant, kOH+dihydromyrcenol, of (38±9) × 10-12 cm3 molecule-1 s-1 was measured using the relative rate technique for the reaction of the hydroxyl radical (OH) with 2,6-dimethyl-7-octen-2-ol (dlhydromyrcenol,) at 297± 3 K and 1 atm total pressure. Additionally, an upper limit of the bimolecular rate constant, & kO3+dihydromyrcenol, of approximately 2 × 10-18 cm3 molecule-1 s-1 was determined by monitoring the decrease in ozone (O 3) concentration in an excess of dihydromyrcenol. To more clearly define part of dihydromyrcenol's indoor environment degradation mechanism, the products of the dihydromyrcenol + OH and dihydromyrcenol + O3 reactions were also investigated. The positively identified dihydromyrcenol/OH and dihydromyrcenol/O3 reaction products were acetone, 2-methylpropanal (O=CHCH(CH3)2), 2-methylbutanal (O=CHCH(CH3)CH2CH3), ethanedial (glyoxal, HC(=O)C(=O)H), 2-oxopropanal (methylglyoxal, CH3C(=O)C(=O)H). The use of derivatizing agents O-(2,3,4,5,6-pentafluorobenzyl)hydroxylamine (PFBHA) and N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA) clearly indicated that several other reaction products were formed. The elucidation of these other reaction products was facilitated by mass spectrometry of the derivatized reaction products coupled with plausible dihydromyrcenol/OH and dihydromyrcenol/O3 reaction mechanisms based on previously published volatile organic compound/OH and volatile organic compound/O3 gas-phase reaction mechanisms.
The competitive and non-competitive hydroformylation of conjugated dienes starting with tetrarhodium dodecacarbonyl. An in-situ high-pressure infrared spectroscopic study
Liu, Guowei,Garland, Marc
, p. 76 - 85 (2007/10/03)
It is well known that the liquid-phase homogeneous unmodified rhodium catalysed hydroformylation of alkenes is poisoned by the presence of trace quantities of conjugated dienes. Nevertheless, some hydroformylation of conjugated dienes is possible with unmodified rhodium, and this reaction is in general slower than alkene hydroformylations at comparable reaction conditions. In the present contribution, we examined (A) the catalytic behaviour of alkenes in the presence of trace conjugated diene impurities and (B) the catalytic behaviour of a variety of dienes using Rh4(CO)12 in n-hexane solvent at 293 K under 1.0-4.0 MPa CO and 0.5-2.0 MPa H2. The analytic method was in-situ high-pressure infrared spectroscopy. It was observed that (I) in the hydroformylation of poisoned alkenes, most of the rhodium reacts with the trace quantity of conjugated dienes and not the alkenes in this competitive situation and (II) the metal carbonyl spectra of the hydroformylation of a variety of dienes are very similar. The primary absorbance maxima observed in the hydroformylations of conjugated dienes occur at circa 2109, 2091, 2087, 2064, 2049, 2037, 2030, 2020, 2012, 1999, and 1990 cm-1. Given the known chemistry Of Rh4(CO)12 under syngas, and the very well documented chemistry of Rh4(CO)12 under alkene hydroformylation conditions, the lack of bridging carbonyls in the present experiments strongly suggested that the new infrared vibrations are due to mononuclear rhodium species. Preliminary analysis suggests the presence of at least three new species. In particular, the formation of observable η3 allyl rhodium tricarbonyl species, σ allyl rhodium tetracarbonyl species and even acyl rhodium tetracarbonyl species RCORh(CO)4 (R = alkenyl and/or formylalkyl) seems probable. Characteristic wavenumbers of 2108, 2064, 2037, 2020 and 1700 cm-1 are tentatively assigned to the latter. The reduced hydroformylation activity in the competitive hydroformylation of alkenes arises due to the much higher affinity of rhodium complexes for conjugated dienes than for alkenes under otherwise similar reaction conditions.
Type III Intramolecular Cycloadditions of Vinylketenes
Snider, Barry B.,Allentoff, Alban J.,Kulkarni, Yashwant S.
, p. 5320 - 5328 (2007/10/02)
Treatment of trans α,β-unsaturated acid chlorides with Et3N in benzene at reflux gives a ca. 1:1 mixture of cis and trans α,β-unsaturated ketenes in excellent yield.If there is a second double bond in the side chain, the cis isomer undergoes a type III intramolecular cycloaddition to produce a bicyclohept-3-en-6-one and/or a bicyclohept-2-en-6-one in 30-50percent yield from the acid chloride.The effect of substituents on the stereochemistry and regiochemistry of the cycloaddition is described.
PALLADIUM(II)-CATALYZED CLAISEN REARRANGEMENT OF ALLYL VINYL ETHERS
Baan, J. L. van der,Bickelhaupt, F.
, p. 6267 - 6270 (2007/10/02)
The Claisen rearrangement of allyl vinyl ethers is catalyzed by PdCl2(CH3CN)2, provided that alkyl substituents protect the vinyl ether double bond from coordination by the metal catalyst.
