108645-56-3Relevant academic research and scientific papers
SYNTHESIS OF (+/-)-GRANDISOL FROM (+) Δ2-CARENE: AN APPLICATION OF PHOTO-INDUCED VINYLCYCLOPROPANE REARRANGEMENT
Sonawane, H. R.,Nanjundiah, B. S.,Kumar, M. Udaya
, p. 2245 - 2246 (1984)
A new synthesis of (+/-)-Grandisol from (+) Δ2-carene involving the photoinduced vinylcyclopropane rearrangement (VCR) as the key step is described.
Ring-Expansion Induced 1,2-Metalate Rearrangements: Highly Diastereoselective Synthesis of Cyclobutyl Boronic Esters
Abell, Joseph C.,Aggarwal, Varinder K.,Fasano, Valerio,Hari, Durga Prasad
, p. 5515 - 5520 (2020)
The broad synthetic utility of organoboron compounds stems from their ready ability to undergo 1,2-migrations. Normally, such shifts are induced by α-leaving groups or by reactions of alkenyl boronates with electrophiles. Herein, we present a new strategy to induce 1,2-metalate rearrangements, via ring expansion of vinylcyclopropyl boronate complexes activated by electrophiles. This leads to a cyclopropane-stabilized carbocation, which triggers ring expansion and concomitant 1,2-metalate rearrangement. This novel process delivers medicinally relevant 1,2-substituted cyclobutyl boronic esters with high levels of diastereoselectivity. A wide range of organolithiums and Grignard reagents, electrophiles, and vinylcyclopropyl boronic esters can be used. The methodology was applied to a short, stereoselective synthesis of (±)-grandisol. Computational studies indicate that the reaction proceeds via a nonclassical carbocation followed by anti-1,2-migration.
Stereoselective total synthesis of (±)-fragranol by TiCl4 promoted [2 + 2] cycloaddition of allyl-tert-butyldiphenylsilane and methyl methacrylate
Knoelker, Hans-Joachim,Baum, Gerhard,Schmitt, Oliver,Wanzl, Guenter
, p. 1737 - 1738 (1999)
A stereoselective total synthesis of the monoterpenoid alcohol (±)-fragranol has been accomplished utilizing a TiCl4 promoted [2 ± 2] cycloaddition of allyl-tert-butyldiphenylsilane and methyl methacrylate as the key step.
A stereospecific synthesis of (±)-grandisol via an intramolecular lactone enolate alkylation: A remarkable regiodivergence in C- vs O-alkylation
Kim,Kwak,Shin
, p. 9211 - 9212 (1994)
(±)-Grandisol (1) has been synthesized in a stereospecific manner by an intramalecular lactone enolate alkylation route featuring remarkable conaol over C- vs O-alkylation.
Catalytic enantioselective synthesis of benzocyclobutenols and cyclobutanolsviaa sequential reduction/C-H functionalization
Chen, Jun,Li, Chunyu,Lu, Ping,Shi, Zhan
, p. 10598 - 10604 (2021)
We report here a sequential enantioselective reduction/C-H functionalization to install contiguous stereogenic carbon centers of benzocyclobutenols and cyclobutanols. This strategy features a practical enantioselective reduction of a ketone and a diastereospecific iridium-catalyzed C-H silylation. Further transformations have been explored, including controllable regioselective ring-opening reactions. In addition, this strategy has been utilized for the synthesis of three natural products, phyllostoxin (proposed structure), grandisol and fragranol.
117. Short Synthesies of (+/-)-Grandisol and (+/-)-Lineatin via a Common Intermediate
Aljancic-Solaja, Ivana,Rey, Max,Dreiding, Andre S.
, p. 1302 - 1306 (1987)
A 6-step synthesis of (+/-)-grandisol (1) is presented, which involves dichloroketene addition to 3-methyl-3-butenyl acetate (4), reductive dechlorination of the adduct 6 to the ketone 7 and saponification to 8, aldolization of 7 or 8 with acetone and cyclization to the bicyclic ketone 9, Wolff-Kishner reduction to 14, and finally ring opening to 1.Since 9 is a known intermediate of the synthesis of (+/-)-lineatin (2), the latter can now be obtained in 6 steps.
A highly stereocontrolled formal total synthesis of (±)- and of (-)-grandisol by 1,4-conjugated addition of organocopper reagents to cyclobutylidene derivatives
Bernard, Angela M.,Frongia, Angelo,Ollivier, Jean,Piras, Pier Paolo,Secci, Francesco,Spiga, Marco
, p. 4968 - 4974 (2008/02/01)
Starting from suitable cyclopropanes, a formal total synthesis of racemic grandisol and of the enantiopure (-)-grandisol is presented. The racemic synthesis of the grandisol precursor was accomplished in five steps. The synthesis of the chiral non-racemic precursor (1S,2S,2′R)-cis of this pheromone was realized in 10 steps, with an overall yield of 45%, using the enantiopure cyclobutanone (R,S), previously obtained by ring expansion of an optically pure oxaspiropentane. The key stereodefining step was the addition of lithium dimethylcuprate to a chiral α,β-unsaturated cyclobutylidene carbonyl derivative.
Stereospecific palladium(0)-catalyzed reduction of 2-cyclobutylidenepropyl esters. A versatile preparation of diastereomeric monoterpenoids: (±)-fragranol and (±)-grandisol
Bernard, Angela M.,Frongia, Angelo,Secci, Francesco,Delogu, Giovanna,Ollivier, Jean,Piras, Pier P.,Salaün, Jacques
, p. 9433 - 9440 (2007/10/03)
Mixtures of (E and Z)-2-cyclobutylidenepropyl sulfonates, readily available from α,α-disubstituted cyclobutanones arising from suitable cyclopropane derivatives ring expansion, underwent regioselective and stereospecific reduction by formate anion to offer, through π-1,1- trimethyleneallylpalladium complexes formed upon treatment with palladium(0), a new and convenient entry to the diastereomeric four-membered ring monoterpenoids (±)-fragranol and (±)-grandisol.
A new stereoselective synthesis of (±)-grandisol based on the remote alkylation protocol
Monteiro, Hugo J.,Stefani, Helio A.
, p. 2659 - 2663 (2007/10/03)
A new stereoselective synthesis of (±)-grandisol (1a) has been developed. The synthesis starts with a simple cyclobutyl derivative to which the methyl group and the 1,2-cis disposed side chains were appended through a remote alkylation protocol.
First total synthesis of the sex pheromone of the oleander scale Aspidiotus nerii: An unusual sesquiterpenic functionalized cyclobutane
Petschen, Inés,Parrilla, Alfredo,Bosch, M. Pilar,Amela, Cristina,Botar, Ana A.,Camps, Francisco,Guerrero, Angel
, p. 3299 - 3309 (2007/10/03)
The first total synthesis of the sex pheromone of the oleander scale Aspidiotus nerii (5), an economically important polyphagous pest, is described. The synthesis is based on a stereo-controlled and completely regioselective intramolecular exo-cyclization of cis-epoxynitrile 9 to afford cyclobutane alcohol t-10 stereoselectively. Introduction of the unusual 4-methylpent-4-enyl group onto the cyclobutane skeleton was effected through Wittig reaction of aldehyde 17b with the bulky ylide 3,3-(ethylenedioxy)butylidenetriphenyl-phosphorane. This process requires protection of the primary hydroxy group of 10 with a nonbulky protecting agent, like methoxymethyl (MOM) but not tetrahydropyranyl (THP), as confirmed by molecular modelling studies. After selective transformations to manipulate the three acid-sensitive protecting functionalities present, that is, the tert-butyl-dimethylsilyl (TBDMS), ethylene acetal, and MOM groups, compound 5 was obtained in 26.4% overall yield from t-10b. In a different approach, complete cleavage of these protecting groups in 19b furnished keto diol 31, which after regioselective acetylation of the primary alcohol and Wittig reaction afforded acetate 5 in 21.4% overall yield from t-10b. The synthetic material exhibited spectroscopic features identical to those of the natural material and showed remarkable biological activity in field tests.
