112635-25-3Relevant articles and documents
Divergent Access to (1,1) and (1,2)-Azidolactones from Alkenes using Hypervalent Iodine Reagents
Alazet, Sébastien,Le Vaillant, Franck,Nicolai, Stefano,Courant, Thibaut,Waser, Jerome
supporting information, p. 9501 - 9504 (2017/07/22)
A versatile synthesis of azidolactones through azidation and cyclization of carboxylic acids onto alkenes has been developed. Based on either photoredox or palladium catalysis, (1,1) and (1,2) azido lactones can be selectively synthesized. The choice of catalyst and benziodoxol(on)e reagent serving as azide source was essential to initiate either a radical or Lewis acid mediated process with divergent outcome. These transformations were carried out under mild conditions using a low catalyst loading and gave access to a large scope of azido lactones.
PLANT GROWTH REGULATING COMPOUNDS
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, (2013/11/19)
The present invention relates to novel strigolactam derivatives of formula (I) to processes and intermediates for pre-paring them, to plant growth regulator compositions comprising them and to methods of using them for controlling the growth of plants and/or promoting the germination of seeds.
STRIGOLACTAM DERIVATIVES AND THEIR USE AS PLANT GROWTH REGULATORS
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, (2012/06/30)
The present invention relates to novel strigolactam derivatives of formula (I) to processes and intermediates for preparing them, to plant growth regulator compositions comprising them and to methods of using them for controlling the growth of plants and/
A new efficient synthesis of GR24 and dimethyl A-ring analogues, germinating agents for seeds of the parasitic weeds Striga and Orobanche spp.
Malik, Heetika,Rutjes, Floris P.J.T.,Zwanenburg, Binne
experimental part, p. 7198 - 7203 (2010/10/02)
An efficient and high yielding preparation for the synthetic germination stimulant GR24 (5) and its A-ring dimethyl-substituted analogues 30-32 has been described. The first step involves a Stobbe condensation of benzaldehydes 9-11 with dimethyl succinate. Subsequent transposition of the ester and reduction of the double bond provides the building blocks 15-17 for an intramolecular Friedel-Crafts acylation. ABC-lactones 22-25 are prepared from γ-keto esters 18-21 by saponification, subsequent reduction with sodium borohydride followed by acid-catalyzed lactonization. Coupling of the lactones with the D-ring is accomplished by formylation and subsequent treatment with bromobutenolide 8 to give GR24 and its dimethyl analogues. Bioassays with Striga hermonthica seeds reveal that the dimethyl analogues are slightly less active than GR24 itself.
Thiol-catalyzed acyl radical cyclization of alkenals
Yoshikai, Kazuya,Hayama, Tomoharu,Nishimura, Katsumi,Yamada, Ken-Ichi,Tomioka, Kiyoshi
, p. 681 - 683 (2007/10/03)
(Chemical Equation Presented) Thiol-catalyzed direct generation of acyl radicals and their intramolecular addition to olefins of alkenals gave 2-substituted five- and six-membered cyclic ketones in reasonably good yields. The combination of odorless tert-dodecanthiol and AIBN or V-40 was the initiator of choice among surveyed radical generators for the cyclization of alkenals. Aldehydes having electron-deficient olefins cyclized more easily than those having unactivated olefins.
Palladium-catalyzed carbonylative cyclization of 1-iodo-2-alkenylbenzenes
Negishi, Ei-Ichi,Copéret, Christophe,Ma, Shengming,Mita, Takeshi,Sugihara, Takumichi,Tour, James M.
, p. 5904 - 5918 (2007/10/03)
The Pd-catalyzed carbonylation of ω-vinyl-substituted o-iodoalkenylbenzenes 1-4 can provide up to modest yields (50-60%) of 5- and 6-membered Type I cyclic acylpalladation products, i.e., α,β-unsaturated cyclic ketones, in the absence of an external nucleophile and high yields of 5- and 6-membered Type II cyclic acylpalladation products, i.e., α- or β-((alkoxycarbonyl)methyl)substituted cyclic ketones in the presence of an alcohol, e.g., MeOH. In cases where no such processes are available, other side reactions, such as cyclic carbopalladation, polymeric acylpalladation, and trapping of acylpalladiums via esterification and other processes may become predominant. Neither smaller, i.e., 3- or 4-membered, nor 7-membered or larger cyclic ketones appear to be accessible by the reaction. In most cases, the exo-mode cyclic acylpalladation takes place exclusively. However, the cyclic acylpalladation of 3 proceeds exclusively via endo-mode cyclization to give 5-membered ketones. Substitution of one or more hydrogens in the ω-vinyl group with carbon groups has significant effects on the reaction course. Those substrates containing a 1,2-disubstituted alkenyl group in place of a vinyl group, i.e., 19-22 and 24 excluding 25, can give monomeric cyclic acylpalladation products in high yields. These results represent a major deviation from those obtained with 1 and 2. In the absence of an external nucleophile, formation of Type I cyclic acylpalladation products is, in some cases, accompanied by Type III cyclic acylpalladation involving trapping of acylpalladiums by internal enolates. In the presence of MeOH or other alcohols, Type II acylpalladation products have been obtained in respectable yields from 19-20, 23, and 24. In the presence of an alcohol, premature esterification can be a serious side reaction. However, this problem can be alleviated using i-PrOH or t-BuOH in place of MeOH in combination with appropriate solvents, typically those of lower polarity. Heteroatom-containing substituents on the ω-vinyl groups also exert significant effects on cyclic acylpalladation. Electron-donating substituents tend to lead to high yields of cyclic acylpalladation products, while electron-withdrawing alkoxycarbonyl groups conjugated with the ω-alkenyl group tend to give lower yields of cyclic acylpalladation products. With Me3Si and alkoxycarbonyl groups products of apparent endo-mode cyclic acylpalladation, i.e., naphthols, have been obtained in significant yields (25-50%). Free OH and other nucleophilic heteroatom groups can seriously interfere with cyclic acylpalladation, and they must be appropriately protected in most cases, although there are indications that acylpalladation-lactonization tandem processes similar to Type II cyclic acylpalladation might be developed.
Acyl Radicals: Intermolecular and Intramolecular Alkene Addition Reactions
Boger, Dale L.,Mathvink, Robert J.
, p. 1429 - 1443 (2007/10/02)
A full study of the use of phenyl selenoesters as precursors to acyl radicals and their subsequent participation in intermolecular and intramolecular alkene addition reactions is detailed.Primary alkyl-, vinyl-, and arylsubstituted acyl radicals generated by Bu3SnH treatment of the corresponding phenyl selenoesters participate cleanly in intermolecular addition reactions with alkenes bearing electron-withdrawing or radical-stabilizing substituents at rates that exceed those of the potentially competitive decarbonylation or reduction.Similarly, their intramolecular addition to activated or unactivated alkenes proceeds without significant competitive reduction or decarbonylation and at rates generally >/= 1 x 106 s-1 with some occuring at rates >/= 3 x 107 s-1.Consistent with their behavior in intermolecular addition reactions, the 5-exo-trig cyclizations of secondary and tertiary alkyl-substituted acyl radicals to an unactivated olefin acceptor may be accompanied by varying degrees of decarbonylation, even under low-temperature free-radical conditions.Studies are presented which suggest that the intramolecular additions of acyl radicals to alkenes under the conditions detailed herein may be regarded as irreversible, kinetically controlled processes which exhibit regioselectivity that is predictable based on well-established empirical rules set forth for the analogous free-radical cyclization reactions of alkyl radicals.
Acyl Radicals: Functionalized Free Radicals for Intramolecular Cyclization Reactions
Boger, Dale L.,Mathvink, Robert J.
, p. 3377 - 3379 (2007/10/02)
A study describing the use of phenyl selenoesters as direct precursors to acyl radicals suitable for the initiation of intramolecular free-radical cyclization reactions is detailed.
