87760-51-8

Upstream product

• 926-56-7 4-methyl-1,3-pentadiene 
• 173917-47-0 1-benzyloxy-4-methylpentan-2-ol 
• 691-37-2 4-Methyl-1-pentene 
• 103260-84-0 4,5-diacetoxy-2-methyl-pent-2-ene 
• 132513-54-3 (S)-2-Hydroxy-4-methyl-pentanoic acid butyl ester 
• 20312-37-2 (R)-2-hydroxy-4-methylpentanoic acid 
• 68113-55-3 1-hydroxy-4-methylpentan-2-one 
• 158393-61-4 2-Diazo-4-methyl-pentanoic acid (1R,2S,5R)-2-isopropyl-5-methyl-cyclohexyl ester 
• 125990-20-7 phyllofoliaspongin 
• 103273-35-4 4-methyl-pent-3-ene-1,2-diol 

Downstream Products

• 111221-87-5 2-hydroxy-4-methylpentyl-p-toluenesulfonate 
• 24347-54-4 (S)-(-)-4-methyl-1,2-pentanediol 
• 23850-78-4 4-methyl-1,2-epoxypentane 

Relevant academic research and scientific papers

Site-selective catalysis: Toward a regiodivergent resolution of 1,2-diols

This paper demonstrates that the secondary hydroxyl can be functionalized in preference to the primary hydroxyl of a 1,2-diol. The site selectivity is achieved by using an enantioselective organic catalyst that is able to bond to the diol reversibly and covalently. The reaction has been parlayed into a divergent kinetic resolution on a racemic mixture, providing access to highly enantioenriched secondary-protected 1,2-diols in a single synthetic step.

Osmium tetroxide in poly(ethylene glycol) (PEG): A recyclable reaction medium for rapid asymmetric dihydroxylation under Sharpless conditions

PEG (400) has been used as a recyclable and rapid reaction medium for the asymmetric dihydroxylation of olefins; Sharpless ligand is efficiently recovered and recycled with good enantioselectivity.

N-(α-chloroalkyloxycarbonyl)pyrrolidines as a source of oxygenated d1- reagents

Reaction of the N-(α-chloroalkyloxycarbonyl)pyrrolidines 1 with lithium powder and a catalytic amount of 4,4'-di-tertbutylbiphenyl (DTBB, 2.5 mol-%) in the presence of different electrophiles [iBuCHO, tBuCHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe, Ph2CO, MeaSiCl], in THF at temperatures ranging between -78 and -60°C leads after hydrolysis with water, to the expected functionalized carbamates 2. Deprotection of compounds 2, derived from carbonyl compounds, with lithium hydroxide in a mixture of ethanol and water at 80°C affords the corresponding 1,2-diols 3.

Preparation of optically active α-Silylcarbonyl compounds using asymmetric alkylation of α-Silylacetic esters and asymmetric metal-carbene insertion into the Si-H bond.

Substituted α-silylacetic esters have been prepared in good yields and with reasonable diastereoselectivities by three different routes. The first two involved alkylation of the parent α-silylacetic ester enolates, with the chiral auxiliaries being present either on silicon or on the ester function. The third route involving asymmetric insertion of metal-carbenoids into the Si-H band was found to afford better diastereoselectivities, using pantolactane as chiral auxiliary.

Kinetic resolution of 2-acylated-1,2-diols by lipase-catalyzed enantiomer selective acylation

Enantiomer selectivity of lipase catalyzed acylation of 2-acylated 1,2-diols was studied. First, acylation of 2-acetoxyheptan-1-ol rac-3b with vinyl acetate was investigated by varying the enzymes and the solvent, showing the highest enantiomer selectivity by using lipase from Pseudomonas fluorescens (PfL) in hexane-vinyl acetate (VA). We have found varying or even reversed enantiomer selectivity for different secondary acyl moieties in 2-acyloxyheptan-1-ols rac-3bA-F. Next, all six possible types of enantiomer selective biotransformations (hydrolysis of diacetate and the two kinds of monoacetetes; acylation of diol and the two kinds of monoacetates) were compared on two model diols rac-4b,d. Among the transformations investigated, acetylation of secondary monoacetates rac-3b,d showed the highest enantiomer selectivity. Finally, PfL catalyzed acetylations of several 2-acetylated 1,2-diols rac-3a-g were investigated under our optimum conditions.

Pheromone synthesis, CLXXVII: Synthesis of the enantiomers of 2-methyl-4-heptanol and 2-methyl-4-octanol, the pheromone components of the West Indian sugarcane borer

Both the enantiomers of 2-methyl-4-heptanol (1) and 2-methyl-4-octanol (2), the components of the male-produced aggregation pheromone of the West Indian sugarcane borer (Metamasius hemipterus), were synthesized by starting from the enantiomers of leucine. VCH Verlagsgesellschaft mbH, 1996.

N-(chloromethyloxycarbonyl)pyrrolidine as a source of the HOCH2- synthon

The reaction of N-(chloromethyloxycarbonyl)pyrrolidine (1) with lithium powder and a catalytic amount of DTBB (2.5 mol %) in the presence of different electrophiles [Me3SiCl, Bu(i)CHO, Bu(t)CHO, PhCHO, Et2CO, (CH2)5CO, PhCOMe, Ph2CO] in THF at -78°C leads, after hydrolysis with water, to the expected functionalised carbamates 2. Deprotection of the acetophenone derivative 2g with DIBALH at THF reflux yields, after hydrolysis, the corresponding 1,2-diol 3g.

SYNTHESIS OF SOME 2'-C-ALKYL DERIVATIVES OF 9-(2-PHOSPHONOMETHOXYETHYL)ADENINE AND RELATED COMPOUNDS

To study the effect of β-substitution in 2'-alkyl derivatives of 9-(2-phosphonomethoxyethyl)adenine (Ia) on the antiviral activity or group specificity, these derivatives were synthesized. 9-(2-Hydroxyalkyl)adenines VIII were prepared by alkylation of adenine with suitably substituted oxiranes XIII or 2-hydroxyalkyl p-toluenesulfonates IV and VI.After protection of the adenine amino group by benzylation (compounds IX) or amidine formation (compounds X), the intermediates were alkylated with bis(2-propyl) p-toluenesulfonyloxymethanephosphonate (XI) in the presence of sodium hydride.After deprotection, the obtained phosphonate diesters XII were converted into phosphoniuc acids I by transsilylation and hydrolysis.This synthetic scheme was used for the preparation of ethyl (Ie), propyl (If), 2-propyl (Ig), 2-methylpropyl (Ih), cyclopropyl (Ii), cyclohexyl (Ij), benzyl (Ik) and phenyl (Il) derivatives.The 2'-trifluoromethyl derivative XXIIa was prepared analogously from 9-(2-hydroxy-3,3,3-trifluoropropyl)adenine (XXa), obtained by alkylation of adenine sodium salt with 2-hydroxy-3,3,3-trifluoropropyl bromide. 2,6-Diaminopurine derivative XXIIb was obtained analogously. 2'-Trimethylsilyl derivative XIXa was obtained by alkylation of adenine with 2-phosphonylmethoxy-3-(4-toluenesulfonyloxy)propyltrimethylsilane (XVII) followed by transsilylation and hydrolysis of diester XVIIIa. 9-(3-Phosphonomethoxybutyl)adenine (XXVIII) and 9-(2-methyl-2-phosphonomethoxypropyl)adenine (XXXV) were prepared from the corresponding hydroxy derivatives XXVIb and XXXII, respectively, by the same reaction pathway as derivatives I.

Substrate Structure and Solvent Hydrophobicity Control Lipase Catalysis and Enantioselectivity in Organic Media

The lipase from Candida cylindracea catalyzes the enantioselective esterification of 2-hydroxy acids in nearly anhydrous organic solvents with primary alcohols as nucleophiles. The nature of the 2-hydroxy acid and organic reaction medium affects the efficiency of catalysis and the enantioselectivity. Straight-chain 2-hydroxy acids are highly reactive and give nearly 100% enantioselectivities in esterification reactions with 1-butanol. Slight branching with a methyl group adjacent to the 2-hydroxy moiety in toluene causes a substantial loss (up to 200-fold) in the lipase's catalytic efficiency with a concomitant loss in enantioselectivity. Losses in catalytic efficiency and enantioselectivity are also observed when the lipase is employed in hydrophilic organic media such as dioxane or tetrahydrofuran as compared to hydrophobic solvents such as toluene. With straight-chain substrates, the lipase is over 100-fold more active in toluene than in tetrahydrofuran or dioxane, while optimal enantioselectivity is observed in toluene. The loss in enantioselectivity in hydrophilic solvents is mainly due to a drop in the catalytic efficiencies of the S isomers, as the R isomers' catalytic efficiencies remain largely unchanged. In highly apolar solvents, such as cyclohexane, enantioselective relaxation occurs due to an increase in the reactivity of the R isomers relative to that of their S counterparts. These findings enabled a rational selection of substrates and solvents for a two-step, chemoenzymatic synthesis of optically active 1,2-diols to be carried out, the first step being the aforementioned enantioselective esterification of 2-hydroxy acids followed by reduction with LiAl(OCH3)3H to give the optically active 1,2-diol. Diols such as (S)-(+)-1,2-propanediol, (S)-(-)-1,2-butanediol, (S)-(-)-1,2-hexanediol, and (S)-(-)-4-methyl-1,2-pentanediol were produced in high optical purities (at least 98% enantiomeric excess (ee)).