66050-76-8

Upstream product

• 1565-80-6 (2S)-2-methyl-1-butanol 
• 20445-31-2 R-(+)-α-trifluoromethyl-α-methoxy-phenylacetic acid 
• 137-32-6 (+/-)-2-methyl-1-butanol 
• 616-16-0 (R)-2-Methyl-1-butanol 
• 39637-99-5 (S)-(+)-2-methoxy-2-trifluoromethyl-2-phenylacetyl chloride 
• 20445-33-4 (R)-methoxytrifluoromethylphenylacetyl chloride 

Relevant academic research and scientific papers

Highly stereoselective allylic ethylation with alkoxytitanacyclopropane reagents. Synthesis of (1R/S,7R)-1,7-dimethylnonyl propanoate, the Western corn rootworm sex attractant

Allylic ethylation of 2-((E)-dodec-2-en-4-yloxy)tetrahydro-2H-pyran with ethylmagnesium bromide in the presence of titanium(IV) isopropoxide proceeds via a SN2′ pathway to afford (E)-3-methyltridec-4-ene with excellent syn-diastereoselecivity. This transformation is used as a key step in the synthesis of (1R/S,7R)-1,7-dimethylnonyl propanoate, the Western corn rootworm (Diabrotica virgifera virgifera) sex attractant.

Synthesis of (4R,8R)- and (4S,8R)-4,8-dimethyldecanal: the common aggregation pheromone of flour beetles

The synthesis of (4R,8R)- and (4S,8R)-4,8-dimethyldecanal 1 and 1a has been achieved connecting the chiral building block (R)-2-methyl-1-bromobutane 4 with (R)- and (S)-citronellol derivatives. The key intermediate 4 was obtained optically pure in five steps from methyl (S)-3-hydroxy-2-methylpropionate 2.

Application of modified Mosher's method for primary alcohols with a methyl group at C2 position.

The absolute configurations of a series of primary alcohols possessing a branched methyl group at C2 position were examined on the basis of a modified Mosher's method proposed by Minale et al. It was revealed that in many cases the absolute configurations

Synthesis of the four possible stereoisomers of N-2′-methylbutyl-2-Methylbutylamide, the sex pheromone of the longhorn beetle Migdolus fryanus westwood

The four stereoisomers of N-2′-methylbutyl-2-methylbutylamide, the sex pheromone of the longhorn beetle Migdolus fryanus, an economically important pest of sugarcane in South America, were synthesized. The key intermediate 2-methylbutan-1-ol is commercially available only in its (S)-(-)-form. The (R)-(+)-enantiomer was obtained optically pure from methyl (S)-(+)-3-hydroxy-2-methylpropionate in five steps.

Assignment of the absolute configuration of β-chiral primary alcohols by NMR: Scope and limitations

The prediction of the absolute configuration of β-chiral primary alcohols from the 1H NMR spectra of their esters with (R)- and (S)- 9-anthrylmethoxyacetic acids (9-AMA, 3) is discussed. Low-temperature NM experiments, MM, semiempirical, ab initio, and aromatic shielding effect calculations allowed the identification of the main conformers and showed that, in all alcohols for which the calculated ΔE(ag) (CVff) is in the range of 0.7-1.5 kcal/mol, conformer a/a is the most stable. A simple model for the assignment of the absolute configuration from NMR data is presented and its reliability corroborated with alcohols (8-20) of known configuration. Nevertheless, cyclic alcohols 21-23 have much higher ΔE(ag) values (2.2-3.1 kcal/mol) due to their different conformational composition, and their absolute configuration cannot be reliably predicted by this method.

Nonreductive enantioselective ring opening of N-(methylsulfonyl)dicarboximides with diisopropoxytitanium α,α,α′,α′-tetraaryl-1,3-dioxolane-4,5- dimethanolate

The bicyclic and tricyclic meso-N-(methylsulfonyl)dicarboximides 1a-f are converted enantioselectively to isopropyl [(sulfonamido)carbonyl]-carboxylates 2a-f by diisopropoxytitanium TADDOLate (75-92% yield; see Scheme 3). The enantiomer ratios of the products are between 86:14 and 97:3, and recrystallization from CH2Cl2/hexane leads to enantiomerically pure sulfonamido esters 2 (Scheme 3). The enantioselectivity shows a linear relationship with the enantiomer excess of the TADDOL employed (Fig. 3). Reduction of the ester and carboxamide groups (LiAlH4) and additional reductive cleavage of the sulfonamido group (Red-Al) in the products 2 of imide-ring opening gives hydroxy-sulfonamides 3 and amino alcohols 4, respectively (Scheme 4). The absolute configuration of the sulfonamido esters 2 is determined by chemical correlation (with 2a, b; Scheme 6), by the X-ray analysis of the camphanate of 3e (Fig. I), and by comparative 19F-NMR analysis of the Mosher esters of the hydroxy-sulfonamides 3 (Table I). A general proposal for the assignment of the absolute configuration of primary alcohols and amines of Formula HXCH2CHR1R2, X = O, NH, is suggested (see 11 in Table I). It follows from the assignment of configuration of 2 that the Re carbonyl group of the original imide 1 is converted to an isopropyl ester group. This result is compatible with a rule previously put forward for the stereochemical course of reactions involving titanium TADDOLate activated chelating electrophiles (12 in Scheme 7). A tentative mechanistic model is proposed (13 and 14 in Scheme 7).

Absolute configuration of main chain of AAL-toxins

AAL-toxins TA1 1 and TA2 2, host-specific toxins produced by Alternaria alternata, were degraded to 2-methylbutanol, 3-methylnonan-1,9-diol and N-protected 4-aminobutan-1,3-diol, which were further converted to (R)-MTPA esters. These esters were correlated with synthetic samples by comparison of their 500 MHz 1H-NMR spectra. The remaining stereocenters were determined by the comparison of 1H-NMR spectra of 6a and 7 derived from 1 and 2 with those of synthetic model compounds. These data conclude that AAL-toxins possess 2S, 4S, 5R, 11S, 13S, 14R and 15R configurations.

Predator - Prey Relationship between Navanax inermis and Bulla gouldiana : a Chemical Approach

Two new compounds, 5,6-dehydroaglajne-3 (9) and isopulo'upone (10), have been isolated and characterized, along with the already known niuhinone-B (7), from Navanax inermis and its prey Bulla gouldiana, firmly establishing on a chemical basis the predator - prey relationship between this pair of cephalaspidean opisthobranchs.The peculiarity of the metabolites and their structural analogy with other compounds isolated from other cephalaspidean molluscs assign a taxonomic relevance for them. Key words: Navanax inermis; Bulla gouldiana; cephalaspidean molluscs; polypropionates.