812697-60-2Relevant academic research and scientific papers
Regiodivergent Hydroborative Ring Opening of Epoxides via Selective C-O Bond Activation
Magre, Marc,Paffenholz, Eva,Maity, Bholanath,Cavallo, Luigi,Rueping, Magnus
supporting information, p. 14286 - 14294 (2020/09/15)
A magnesium-catalyzed regiodivergent C-O bond cleavage protocol is presented. Readily available magnesium catalysts achieve the selective hydroboration of a wide range of epoxides and oxetanes yielding secondary and tertiary alcohols in excellent yields and regioselectivities. Experimental mechanistic investigations and DFT calculations provide insight into the unexpected regiodivergence and explain the different mechanisms of the C-O bond activation and product formation.
Incubation of 2-methylisoborneol synthase with the intermediate analog 2-methylneryl diphosphate
Chou, Wayne K.W.,Gould, Colin A.,Cane, David E.
, p. 625 - 631 (2017/05/29)
Incubation of synthetic 2-methylneryl diphosphate (2-MeNPP, 10) with 2-methylisoborneol synthase (MIBS) gave a mixture of products that differed significantly from that derived from the natural substrate (E)-2-methylgeranyl diphosphate (3, 2-MeGPP). The proportion of (-)-2-methylisoborneol (1) decreased from 89 to 17% while that of 2-methylenebornane (4) increased from 10 to 26%, with the relative yields of the isomeric homo-monoterpenes 2-methyl-2-bornene (5) and 1-methylcamphene (6) remaining essentially unchanged (a k cat 0.105±0.007 s -1, K m 95±49 μm and k cat /K m 1.11 × 10 3 M -1 s -1. Taken together with earlier X-ray crystallographic studies of MIBS, as well as previous investigations of the mechanistically related plant monoterpene cyclase, bornyl diphosphate synthase, these results provide important insights into the binding and cyclization of both native substrates and intermediates and their analogs.
Biochemistry and molecular genetics of the biosynthesis of the earthy odorant methylisoborneol in Streptomyces coelicolor
Wang, Chieh-Mei,Cane, David E.
supporting information; experimental part, p. 8908 - 8909 (2009/02/03)
Methylisoborneol (2) is a volatile organic compound produced by a wide variety of Actinomycete soil organisms, myxobacteria, and cyanobacteria. It has an unusually low odor threshold and, together with geosmin, is responsible for the characteristic smell of moist soil as well as unpleasant taste and odor episodes associated with public water supplies and contamination of various foodstuffs, including fish, wine, and beer. Despite considerable interest in detection and remediation of methylisoborneol, the biosynthesis of this methylated monoterpene has been obscure. In Streptomyces coelicolor, the sco7700 and sco7701 genes are shown to correspond to a two-gene operon responsible for methylisoborneol biosynthesis. Both genes have been amplified by PCR and the resulting DNA has been cloned and expressed in Escherichia coli. Incubation of recombinant SCO7701 protein, annotated as a possible C-methyltransferase, with geranyl diphosphate (1) and S-adenosylmethionine gave the previously unknown compound, (E)-2-methylgeranyl diphosphate (3). Incubation of 3 in the presence of Mg2+ with recombinant SCO7700, previously annotated only as a possible metal-binding protein or terpenoid synthase, resulted in the formation of 2-methylisoborneol (2). The steady-state kinetic parameters for both biochemical reactions have been determined. Incubation of geranyl diphosphate and S-adenosylmethionine with a mixture of both SCO7700 and SCO7701 resulted in formation of methylisoborneol (2). Cyclization of 2-methylgeranyl diphosphate (3) to methylisoborneol (2) likely involves the intermediacy of 2-methyllinalyl diphosphate. Copyright
Biosynthesis of the off-flavor 2-methylisoborneol by the myxobacterium Nannocystis exedens
Dickschat, Jeroen S.,Nawrath, Thorben,Thiel, Verena,Kunze, Brigitte,Mueller, Rolf,Schulz, Stefan
, p. 8287 - 8290 (2008/09/18)
(Chemical Equation Presented) A bouquet of bacteria: Methylisoborneol (1) is a widely occurring volatile from bacteria and an undesirable flavor (off-flavor) in the food industry. The analysis of isotopomers obtained by feeding isotopically labeled precursors to myxobacteria revealed the biosynthetic pathway to 1. Geranylpyrophosphate (CPP) is alkylated by S-adenosylmethionine (SAM) and the product is cyclized to 1. The methylation of GPP is unprecedented in nature.
Unusual cyclopropanation of 9-bromocamphor derivatives: A novel formal C(1)-C(7) bond cleavage of camphor
Li, Wei-Dong Z.,Yang, Yu-Rong
, p. 3107 - 3110 (2007/10/03)
(Chemical Equation Presented) An unusual cyclopropanation of 9-bromocamphor derivatives 1 to a 7-spiro-cyclopropyl camphor derivative 3 was effected by the action of potassium tert-butoxide (or sodium hydride) in warm DMSO. The exo-hydroxy group and a non
Asymmetric Conversion of Arenechromium Complexes to Functionalized Cyclohexenones: Progress toward Defining an Optimum Chiral Auxiliary
Pearson, Anthony J.,Gontcharov, Alexander V.
, p. 152 - 162 (2007/10/03)
An investigation into the asymmetric synthesis of 5-substituted cyclohexenones via nucleophile addition to (alkoxyarene)chromium tricarbonyl complexes is described. Diastereoselectivity during the nucleophile addition step was achieved using alkoxy substituents derived from terpenoid substrates as chiral auxiliaries. Selectivities as high as 24:1 were obtained when 2-phenylisoborneol was used as the chiral auxiliary and as high as 17:1 using 3,3-(ethylenedioxy)isoborneol. The absolute stereochemistry of the major products was assigned by Mosher's method, after their conversion to the corresponding cyclohexenol. A study of the temperature dependence of the nucleophile addition to alkoxytoluene complexes revealed a thermodynamic preference for addition ortho to the ether substituent.
Anhydrous cerium(III) chloride - Effect of the drying process on activity and efficiency
Dimitrov, Vladimir,Kostova, Kalina,Genov, Miroslav
, p. 6787 - 6790 (2007/10/03)
The activity and efficiency of anhydrous CeCl3 depend strongly on the drying procedure. Deactivation of CeCl3 occurs during the drying process as a result of hydrolysis by the hydrate water, when heating above 90°C. The highly active CeCl3, prepared by an improved drying procedure, is demonstrated to activate rapidly (in catalytic and stoichiometric amounts) ketones at room temperature, providing excellent addition of organimetallic reagents.
SYNTHESIS OF 1,4,7,7-TETRAMETHYLBICYCLOHEPT-exo-2-YLACYLAMINES
Kozlov, N. G.,Popova, L. A.,Knizhnikov, V. A.
, p. 666 - 668 (2007/10/03)
A procedure has been developed for the selective preparation of 2-methylisoborneol by the action of methyllithium on camphane.It has been shown that the interaction of 2-methylisoborneol with aceto- and benzonitriles in the presence of sulfuric acid gives, as the results of a rearrangement of the carbon skeleton, high yields of the corresponding 1,4,7,7-tetramethylibicyclohept-exo-2-ylacylamines, which possess an anticataleptic action.
CERIUM(III) CHLORIDE AS CATALYTIC AND STOICHIOMETRIC PROMOTER OF THE QUANTITATIVE ADDITION OF ORGANOMETALLIC REAGENTS TO (+)-CAMPHOR AND (-)-FENCHONE
Dimitrov, Vladimir,Bratovanov, Svetoslav,Simova, Svetlana,Kostova, Kalina
, p. 6713 - 6716 (2007/10/02)
Quantitative addition of organolithium and Grignard reagents to camphor (1) and fenchone (2) proceeds via precomplexation of the ketone with CeCl3 at room temperature.Excellent addition using catalytic or substoichiometric amounts of CeCl3 is demonstrated
SIMPLE CAMPHOR DERIVATIVES AS CHIRAL AUXILIARIES FOR ASYMMETRIC CONJUGATE ADDITION
Somfai, Peter,Tanner, David,Olsson, Thomas
, p. 5973 - 5980 (2007/10/02)
The chiral enoates, 4, readily available in two simple steps from (+)-camphor, undergo asymmetric conjugate addition with the Gilman reagent LiBu2Cu.Chemical yields are high (70-90percent) and in the case of the naphthyl-substituted enoate 4e excellent diastereoselectivity (95percent d.e.) is observed. 3-Methyl-heptan-1-ol of correspondingly high enantiomeric purity is obtained by reduction of the conjugate adduct with lithium aluminium hydride.
