17226-65-2

Upstream product

• 5660-61-7 (R,R) and (S,S)-2,2,4,5-tetramethyl-1,3-dioxolane 
• 67-64-1 acetone 
• 21490-63-1 2,3-trans-epoxybutane 
• 1029272-42-1 (2R,3S)-2,3-butanediol 

Downstream Products

• 513-86-0 3-hydroxy-2-butanon 
• 5660-61-7 (R,R) and (S,S)-2,2,4,5-tetramethyl-1,3-dioxolane 

Relevant academic research and scientific papers

Synthesis of acetonides from epoxides catalyzed by erbium(III) triflate

Epoxides dissolved in acetone can be converted almost quantitatively in acetonides in the presence of catalytic amounts of erhium(III) triflate. The procedure can be usefully applied to other substrates and can be extended to other ketones.

Selective radical-chain epimerisation at electron-rich chiral tertiary C-H centres using thiols as protic polarity-reversal catalysts

Radical-chain epimerisation at chiral tertiary CH centres adjacent to ethereal oxygen atoms can be brought about in the presence of thiols, the function of which is to act as protic polarity-reversal catalysts for hydrogen-atom transfer between pairs of nucleophilic α-alkoxyalkyl radicals. The viability of the method is demonstrated by epimerisation of a series of simple molecules that contain two chiral centres and then the procedure is applied to more complex carbohydrate-based systems, where it is possible to convert a readily available diastereoisomer into a rarer one in a straightforward manner. Of necessity, epimerisation always proceeds in the direction of thermodynamic equilibrium and, in general, the results obtained are in accord with the predictions of molecular mechanics calculations using the MMX force-field. When the required isomer is less stable than the starting diastereoisomer, thiol-catalysed epimerisation of a suitable derivative of the parent can provide a means to obtain the desired compound in satisfactory yield, after deprotection of the epimerised derivative. This strategy is demonstrated for the conversion of trans-cyclohexane-1,2-diol into the less stable cis-isomer and for related contra-thermodynamic isomerisation of some carbohydrates, as well as for the conversion of meso-1,2-diphenylethane-1,2-diol into the dl-form. Thiol-catalysed epimerisation at a CH centre adjacent to an ether-oxygen atom is much faster than at a similar centre adjacent to an amido-nitrogen atom, a result that can be understood in terms of the importance of polar effects on the rate of abstraction of hydrogen by electrophilic thiyl radicals.

Synthesis of 1,3-dioxolanes by the addition of ketones to epoxides by using [Cp*Ir(NCMe)3]2+ as catalyst

A series of 1,3-dioxolanes have been prepared by the addition of ketones to epoxides in the presence of the catalyst [Cp*Ir(NCMe)3]2+, Cp=C5Me5. The reactions proceed readily at 22°C and the yields are good. The following 1,3-dioxolanes: 2,2,4-trimethyl-1,3-dioxolane, 1; 2,2-dimethyl-4-vinyl-1,3-dioxolane, 2; 2,2-dimethyl-4-phenyl-1,3-dioxolane, 3; 2,2-diethyl-4-methyl-1,3-dioxolane, 4; 2,2-diethyl-4-vinyl-1,3-dioxolane, 5; 2,2-diethyl-4-phenyl-1,3-dioxolane, 6 were prepared from the appropriate epoxide and carbonyl compounds. An inversion of configuration at the carbon atom at the C-O bond cleavage site of the epoxide was observed to occur in the formation of the dioxolanes: R, S,- 2,2,4,5-tetramethyl-1,3-dioxolane, 7 and a mixture of R,R- and S,S-2,2,4,5-tetramethyl-1,3-dioxolane, 8 obtained from the reactions of acetone with R, R,-/S, S,-buten-2-oxide and R, S,-buten-2-oxide, respectively.

Selective radical-chain epimerisation at C-H centres α to oxygen under conditions of polarity-reversal catalysis

Polarity-reversal catalysis by tri-tert-butoxysilanethiol has been applied to promote radical-chain epimerisation selectively at carbon centres of the type R1R2C*(H)OR.