Application of1H NMR and13C NMR for establishing the spatial structure of stereoisomeric o- and p-menthane, o- and p-menthenes, and isopropylcyclohexane

Bazyl'chik, V. V.; Samitov, Yu. Yu.; Ryabushkina, N. M.

doi:10.1007/bf00612941

Cited by 2 publications

(2 citation statements)

References 4 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The reaction of 1-methylcyclohexene ( 6 ) (0.48 g, 5 mmol) and isopropyl chloroformate ( 12a ) (0.7 g, 5 mmol) was carried out as described (procedure 1) and gave, after purification of the crude product by Kugelrohr distillation, 0.44 g (49%) of 24 as a diastereomeric mixture ([ trans - 24 ]:[ cis - 24 ] = 1.5:1). Trans - and cis - 24 were characterized by their MS and NMR data; the latter are in agreement with the corresponding data given in ref .…”

Section: Methodssupporting

confidence: 87%

Alkylation of Alkenes: Ethylaluminum Sesquichloride-Mediated Hydro-Alkyl Additions with Alkyl Chloroformates and Di-tert-butylpyrocarbonate

Biermann

Metzger

2004

J. Am. Chem. Soc.

View full text Add to dashboard Cite

A general method for the hydro-alkyl addition to the nonactivated C=C double bond of alkenes using alkyl chloroformates (primary, secondary), 12, and di-tert-butylpyrocarbonate, 52, mediated by ethylaluminum sesquichloride (Et(3)Al(2)Cl(3)) has been developed. Reaction of 12 and 52, respectively, with Et(3)Al(2)Cl(3) gives an alkyl cation which is added to the alkene; hydride transfer to the adduct carbenium ion or, if applicable, 1,2-H shift followed by hydride transfer from Et(3)Al(2)Cl(3) to the rearranged adduct carbenium ion gives the saturated addition product. The reaction has been applied to 1-alkenes, 2-methyl-1-alkenes, internal double bonds, and to three cyclic alkenes. Special interest has been focused on alkylations of unsaturated fatty compounds, such as oleic acid (2), which are important renewable feedstocks. 2-Methylalkanes, 3-methylalkanes, 2,4-dimethylalkanes, 2,3-dimethylalkanes, 2,2,4-trimethylalkanes, cyclohexylalkanes, and carboxylic acids and esters with the respective branched alkyl chain have been synthesized with good to moderate yields.

show abstract

Section: Methodssupporting

confidence: 87%

Alkylation of Alkenes: Ethylaluminum Sesquichloride-Mediated Hydro-Alkyl Additions with Alkyl Chloroformates and Di-tert-butylpyrocarbonate

Biermann

Metzger

2004

J. Am. Chem. Soc.

View full text Add to dashboard Cite

show abstract

“…Signal sets for 2-menthene ( 8 ; 10 peaks, 19–24 area %) and 3-menthene ( 9 ; 10 peaks, 10–12 area %) were assigned by reference data . Out of 26 major peaks (40–120 area %), six were assigned to trans - p -menthane ( 4 ) and 10 each to the predominant organomagnesium species 1a′ / b′ . Connectivity and peak assignments for 1a′ / b′ and 4 were elucidated by 2D NMR methods (HSQC, HMBC).…”

Section: Resultsmentioning

confidence: 99%

Stereochemistry of the Menthyl Grignard Reagent: Generation, Composition, Dynamics, and Reactions with Electrophiles

et al. 2018

View full text Add to dashboard Cite

Menthyl Grignard reagent 1 from either menthyl chloride (2) or neomenthyl chloride (3) consists of menthylmagnesium chloride (1a), neomenthylmagnesium chloride (1b), trans-p-menthane (4), 2-menthene (8), 3-menthene (9), and Wurtz coupling products including symmetrical bimenthyl 13. The diastereomeric ratio 1a/1b was determined in situ by 13 C NMR or after D 2 O quenching by 2 H NMR analysis. Hydrolysis of the C−Mg bond proceeds with retention of configuration at C-1. The kinetic ratio 1a/1b from Grignard reagent generation (dr 59:41 at 50 °C in THF) is close to the thermodynamic ratio (56:44 at 50 °C in THF). Carboxylation of 1 at −78 °C separates diastereomers 1a/b to give the anion of menthanecarboxylic acid (19) from 1a, which combines with unreactive 1b to give neomenthylmagnesium menthanecarboxylate (1b I ). The kinetics of epimerization for the menthyl/neomenthylmagnesium system was analyzed (ΔH ⧧ = 98.5 kJ/mol, ΔS ⧧ = −113 J/mol•K for 1b I → 1a I ). Reactions of 1 with phosphorus electrophiles proceed stereoconvergently at C-1 of 1a/b to give predominantly menthyl-configured substitution products: PCl 3 and 2 equiv of 1 give Men 2 PCl (6), which hydrolyzes to dimenthylphosphine P-oxide (7), whereas Ph 2 PCl with 1 equiv of 1 gave Pmenthyldiphenylphosphine oxide (27) after workup in air.

show abstract

Application of1H NMR and13C NMR for establishing the spatial structure of stereoisomeric o- and p-menthane, o- and p-menthenes, and isopropylcyclohexane

Cited by 2 publications

References 4 publications

Alkylation of Alkenes: Ethylaluminum Sesquichloride-Mediated Hydro-Alkyl Additions with Alkyl Chloroformates and Di-tert-butylpyrocarbonate

Alkylation of Alkenes: Ethylaluminum Sesquichloride-Mediated Hydro-Alkyl Additions with Alkyl Chloroformates and Di-tert-butylpyrocarbonate

Stereochemistry of the Menthyl Grignard Reagent: Generation, Composition, Dynamics, and Reactions with Electrophiles

Contact Info

Product

Resources

About