63846-76-4

Usage

Synthesis Reference(s)

Journal of the American Chemical Society, 99, p. 5213, 1977 DOI: 10.1021/ja00457a069

InChI:InChI=1/C18H28O2/c1-8-20-18(19)17-15(12(4)5)9-14(11(2)3)10-16(17)13(6)7/h9-13H,8H2,1-7H3

Upstream product

• 21524-34-5 2,4,6-triisopropyl-1-bromobenzene 
• 105-58-8 Diethyl carbonate 
• 49623-71-4 2,4,6-triisopropylbenzoic acid 
• 64-17-5 ethanol 
• 78-39-7 Triethyl orthoacetate 
• 57199-00-5 2,4,6-triisopropylbenzoyl chloride 
• 74-96-4 ethyl bromide 

Downstream Products

• 77256-51-0 α-(1-Hydroxycyclohexyl)-ethyl-2,4,6-triisopropylbenzoat 
• 5396-58-7 2-methyl-2,3-butanediol 
• 68027-59-8 3-Hydroxy-3-methyl-but-2-yl-(2,4,6-triisopropylbenzoat) 
• 77256-50-9 2,4,6-Triisopropyl-benzoic acid 1-methyl-pentyl ester 
• 4276-88-4 [2,4,6-tris(1-methylethyl)phenyl]methanol 
• 174090-36-9 4,4,5,5-tetramethyl-2-(1-phenyl-ethyl)-[1,3,2]dioxaborolane 
• 1338073-35-0 (S)-2-(4-(4-methoxyphenyl)butan-2-yl)-4,4,5,5-tetramethyl-1,3,2-dioxaborolane 

Relevant academic research and scientific papers

Desymmetrization of C2-Symmetric Bis(Boronic Esters) by Zweifel Olefinations

anti-Configured 1,3-dimethyl deoxypropionate motifs are important sub structures in natural products. Herein, we describe a bidirectional approach for the rapid construction of natural products featuring such motifs by using C2-symmetrical 1,3-bis(boronic esters). As for its application in convergent syntheses it was important to establish a selective mono-Zweifel olefination we describe the scope and limitations by using different 1,3-bis(boronic esters) and nucleophiles. This protocol takes advantage of the combination of the Hoppe–Matteson–Zweifel chemistry, which was elegantly put into practice by Aggarwal et al. In order to show its applicability the total syntheses of two natural products, serricornin and (+)-invictolide, were performed.

Investigation of the Deprotonative Generation and Borylation of Diamine-Ligated α-Lithiated Carbamates and Benzoates by in Situ IR spectroscopy

Diamine-mediated α-deprotonation of O-alkyl carbamates or benzoates with alkyllithium reagents, trapping of the carbanion with organoboron compounds, and 1,2-metalate rearrangement of the resulting boronate complex are the primary steps by which organoboron compounds can be stereoselectively homologated. Although the final step can be easily monitored by 11B NMR spectroscopy, the first two steps, which are typically carried out at cryogenic temperatures, are less well understood owing to the requirement for specialized analytical techniques. Investigation of these steps by in situ IR spectroscopy has provided invaluable data for optimizing the homologation reactions of organoboron compounds. Although the deprotonation of benzoates in noncoordinating solvents is faster than that in ethereal solvents, the deprotonation of carbamates shows the opposite trend, a difference that has its origin in the propensity of carbamates to form inactive parasitic complexes with the diamine-ligated alkyllithium reagent. Borylation of bulky diamine-ligated lithiated species in toluene is extremely slow, owing to the requirement for initial complexation of the oxygen atoms of the diol ligand on boron with the lithium ion prior to boron-lithium exchange. However, ethereal solvent, or very small amounts of THF, facilitate precomplexation through initial displacement of the bulky diamines coordinated to the lithium ion. Comparison of the carbonyl stretching frequencies of boronates derived from pinacol boronic esters with those derived from trialkylboranes suggests that the displaced lithium ion is residing on the pinacol oxygen atoms and the benzoate/carbamate carbonyl group, respectively, explaining, at least in part, the faster 1,2-metalate rearrangements of boronates derived from the trialkylboranes.

Enantioselective α-arylation of O-carbamates via sparteine-mediated lithiation and Negishi cross-coupling

A general and highly enantioselective arylation of carbamates derived from primary alcohols was developed by combining Hoppe's sparteine-mediated asymmetric lithiation with Negishi cross-coupling. Coupled with Aggarwal's lithiation-borylation sequence, the current method provides a short and divergent access to a variety of enantioenriched secondary and tertiary benzylic alcohols.

Highly diastereo- and enantioselective allylboration of aldehydes using α-substituted allyl/crotyl pinacol boronic esters via in situ generated borinic esters

Readily available, α-substituted allyl/crotyl pinacol boronic esters often give low E/Z selectivity (with Z favored) in reactions with aldehydes. We found that addition of nBuLi to the pinacol boronic ester followed by trapping of the alkoxide with TFAA leads to an intermediate allyl borinic ester which undergoes allylboration with very high E selectivity. The substrate scope includes primary to tertiary alkyl α-substituents, crotyl substrates, and the previously unreported β-methallyl pinacol boronic esters. The latter give very high Z selectivity under standard conditions which is completely reversed to high E selectivity under the new conditions. Monitoring the reaction by 11B NMR confirmed that the reaction proceeds through a borinic ester intermediate.

Stereocontrolled asymmetric synthesis of syn-E-1,4-diol-2-enes using allyl boronates and its application in the total synthesis of solandelactone F

The solandelactones A-H comprise a novel class of oxygenated fatty acids bearing an eight-membered lactone, trans cyclopropane, and a 2-ene-1,4-diol subunit. The relative stereochemistry of the 1,4-diol subunit is anti in solandelactones A, C, E & G, and

Use of alkyl 2,4,6-triisopropylbenzoates in the asymmetric homologation of challenging boronic esters

(-)-Sparteine induced lithiation of primary 2,4,6-triisopropylbenzoates and subsequent homologation of boronic esters is reported. A comparative study with lithiated N,N-diisopropylcarbamates has demonstrated the superiority of the hindered benzoate. The Royal Society of Chemistry 2011.

Synthesis and reactivity of an unprecedented osmium(VIII) alkylidene

The synthesis of a family of Os(VIII) alkylidene complexes, the highest oxidation state alkylidenes known to date, and their reactivity toward small organic molecules are reported.

Efficient esterification of carboxylic acids and phosphonic acids with trialkyl orthoacetate in ionic liquid

An operationally simple, inexpensive, efficient, and environmentally friendly esterification of various carboxylic acids, phosphonic acids, and phosphinic acids with triethyl orthoacetate or trimethyl orthoacetate under neutral conditions in a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, was successfully carried out to provide the corresponding ethyl esters or methyl esters in high yields.

Environmentally friendly esterification of carboxylic acids with triethyl orthoacetate in ionic liquid

An operationally simple, inexpensive, efficient, and environmentally friendly esterification of carboxylic acids with triethyl orthoacetate under neutral conditions in a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate, was carried out to provide the corresponding ethyl esters in high yields.

Dipole-Stabilized Carbanions from Esters: α-Oxo Lithiations of 2,6-Substituted Benzoates of Primary Alcohols

The synthetic utility of dipole-stabilized carbanions from esters is illustrated by the preparations, α-oxo lithiations, electrophilic substitutions, and cleavages of the 2,4,6-triisopropylbenzoates and the 2,6-bis(dimethylamino)-3,5-diisopropylbenzoates of primary alcohols, 2 and 3, respectively.Typical electrophiles used in this methodology include primary alkyl halides, aldehydes, ketones, trimethylsilyl chloride, and tri-n-butyltin chloride.Cleavages of the substituted esters of 2 are accomplished with lithium aluminum hydride while hydrolyses of derivatives of3 can be achieved under acidic conditions.The 2,6-substitutions of 2 and 3 are considered to enforce orthogonality of the carbonyl group and the phenyl ring and thereby to inhibit addition to the carbonyl by the organolithium base used for the metalation by placing the substituents in the trajectory for nucleophilic addition along the LUMO of the carbonyl.The acidic hydrolysis of 3 under conditions where 2 is stable is attributed to protonation of the dimethylamino group which provides subsequent assistance for nucleophilic addition.These metalations provide the key steps in the preparation of secondary α-lithio alcohol synthetic equivalents from primary alcohols.Lithiation of 1'-methylbenzyl 2,4,6-triisopropylbenzoate proceeds α to oxygen as expected, but attempts to prepare analogous unactivated tertiary α-lithio esters were unsuccessful.The lithiation of 2'-methoxyethyl 2,4,6-triisopropylbenzoate is followed by elimination of methoxide and α-oxo metalation of the resulting vinyl ester.Lithiation of allyl 2,4,6-triisopropylbenzoate provides 1-(2,4,6-triisopropylphenyl)-1,2-butanedione by rearrangement.