74066-96-9Relevant academic research and scientific papers
Asymmetric Construction of Alkaloids by Employing a Key ω-Transaminase Cascade
Taday, Freya,Ryan, James,Argent, Stephen P.,Caprio, Vittorio,Maciá, Beatriz,O'Reilly, Elaine
supporting information, p. 3729 - 3732 (2020/03/11)
An ω-transaminase-triggered intramolecular aza-Michael reaction has been employed for the preparation of cyclic β-enaminones in good yield and excellent enantio- and diastereoselectivity, starting from easily accessible prochiral ketoynones and commercially available enzymes. The powerful thermodynamic driving force associated with the spontaneous aza-Michael reaction effectively displaces the transaminase reaction equilibrium towards product formation, using only two equivalents of isopropylamine. To demonstrate the potential of this methodology, this biocatalytic aza-Michael step was combined with annulation chemistry, affording unique stereo-defined fused alkaloid architectures.
Stoichiometric and catalytic reductive aldol cyclizations of alkynediones induced by Stryker's reagent
Chiu, Pauline,Leung, Sze Kar
, p. 2308 - 2309 (2007/10/03)
Conjugate reduction of alkynones by stoichiometric [(Ph3P)CuH] 6 or catalytic [(Ph3P)CuH]6 and polymethylhydrosiloxane proceeds to cyclization by an aldol reaction with tethered ketones to generate β-hydroxyenon
Identification and synthesis of volicitin and related components from beet armyworm oral secretions
Alborn,Jones,Stenhagen,Tumlinson
, p. 203 - 220 (2007/10/03)
Oral secretion of beet armyworm caterpillars (BAW), when applied to damaged tissues of corn seedlings, induces the seedlings to emit volatile compounds that attract the natural enemies of the caterpillars. The key elicitor present in BAW oral secretions is N-[17-hydroxylinolenoyl]-L- glutamine (volicitin). Analysis of the oral secretion showed that it also contained N-[17-hydroxyolinoleoyl]-L-glutamine, free 17-hydroxylinolenic, and 17-hydroxylinoleic acid, the glutamine conjugates of linolenic and linoleic acid as well as free linolenic and linoleic acid. Here we present the identification and synthesis of the hydroxy acids and of glutamine conjugates.
Reductive Cyclization of Ketones Tethered to Activated Olefins Mediated by Magnesium in Methanol
Lee, Ge Hyeong,Choi, Eun Bok,Lee, Eun,Pak, Chwang Siek
, p. 1428 - 1443 (2007/10/02)
The reductive cyclization of various ketones tethered to activated olefins such as α,β-unsaturated esters, nitriles, sulfoxides, and sulfides mediated by magnesium in dry methanol in the presence of mercuric chloride.When traeted with magnesium in dry methanol at -23 deg C all of the ketones except nitrile 9 (42percent) and 5-oxa-8-keto-2-enoate 5 (13percent) gave excellent yields (79-98percent) of mono- and bicyclic alcohol products resulting from carbon-carbon bond formation between the β-carbon of the activated olefin and the carbonyl carbon.The reaction was accelerated by the catalytic amount of mercuric chloride, although the stereoselectivity was not affected by the catalyst.For all the substrates except 8-keto-2-enoate 3 and 5-aza-8-keto-2-enoate 6, the configuration of the major product was trans between the hydroxy and (methoxycarbonyl)methyl groups.The product isomer ratios were independent of the substrate geometry (E or Z).In contrast to the ketones, aldehydes tethered to α,β-unsaturated esters gave products of simple reduction of the double bond and/or saturated alcohols instead of the cyclized products.When the reaction temperature was lowered, the yields of cyclized product were significantly affected by the production of appreciable amounts of saturated product, but the stereoselectivity was not improved.Under the same reaction conditions α,β-unsaturated sulfoxide 16 gave deoxygenated sulfide 18 (85percent) as the major product along with a small amount (9percent) of cyclized product 19t.In contrast, sulfone 17 underwent desulfonylation instead of cyclization to give olefin 20 (54percent).With excess magnesium (15 equiv), however, α,β-unsaturated sulfoxide 16 gave cyclized sulfide 19t (95percent) via deoxygenated sulfide 18.Both 16Z and 16E afforded product 19t as a single isomer.It is suggested that the reductive cyclization of the α,β-unsaturated esters and nitriles proceed by means of nucleophilic attack of a β-carbon radical anion, formed by initial electron transfer from magnesium metal to the activated olefin, on the carbonyl group.The cyclization of the α,β-unsaturated sulfide proceeds by nucleophilic attack of the ketyl on the olefinic double bond.
Metal-Catalyzed Organic Photoreactions. Bond-Cleavage Selectivity and Synthetic Application of the Iron(III) Chloride Catalyzed Photooxidation of Cyclic Olefins
Kohda, Akira,Nagayoshi, Kazuo,Maemoto, Kazuo,Sato, Tadashi
, p. 425 - 432 (2007/10/02)
Photooxidation of olefins in pyridine in the presence of iron(III) chloride produced either α-chloro ketones (type A), gem-dichloro ketones (type B), or α,ω-dichloro ketones (type C), depending upon the substitution pattern of the substrate olefin.The synthetic utility of the type B reaction was demonstrated by the synthesis of some natural products.The synthesis of optically active solanone from D-p-menthene confirmed the D configuration of the natural product.
