Ketene N,N-acetals ( I ) and ketene 0,N-acetals (2) containing hydrogen in the 2-position afford P-substitution products when treated with compounds such as isocyanates and isothiocyanates that contain an electrophilic double bond system[l~zl. However, azosulfones (3) [31 and N-sulfonylimines (7) [41 react with ketene N,N-acetals ( I ) by cycloaddition, affording the hitherto unknown 1,2-dihydr...

Transformation of acetals into ethers by partial reduction using a samarium diiodide-Lewis acids-acetonitrile system is described. The reaction with aromatic acetals occurred in good yields in the presence of aluminum chloride (2 eq) whereas the corresponding aliphatic, vinylic, and alkynyl derivatives did not afford ethers under the same conditions. Beta-elimination to give an enol ether becom...

Polymeric dicyanoketene acetals (DCKA) were synthesized by copolymerization of styrene and divinylbenzene or ethylene glycol dimethacrylate. These novel polymers could be used successfully as recyclable pi-acid catalysts in monothioacetalization or carbon-carbon bond forming reaction of acetals.

We describe the first synthesis of homoallyl ethers from acetals and allyltrimethylsilane using microwave heating and CuBr as a promoter. This method works best for aromatic acetals, giving the corresponding homoallyl ethers in good to quantitative yield.

Secondary phosphine oxides R2P(O)H are a relatively stable tautomeric form of secondary phosphinous acids R2P–OH that with imine/iminium species, or their donors, compounds P(O)–Csp3–N linkage (the phospha-Mannich reaction). These can be referred to as (α-aminoalkyl)phosphine oxides, (α-phosphinoylalkyl)amines, P(O),N-acetals. Compared P–Csp3–N linkages P,N-acetals, products reactions involving...

α-Bromoketals and acetals are important synthetic precursors in organic synthesis. In this work, some new α-bromoketals are synthesized by the reaction of aryl methyl ketones with diols in the presence of 1,8-diazabicyclo[5.4.0] undec-7-ene (DBU) hydrobromide-perbromide in good isolated yields. The latter compound converts aldehydes to acetals and serves as a new and efficient reagent for t...

Saturated and unsaturated fatty aldehydes were prepared in good yield by the reduction of acid chlorides with lithium aluminum tri-t-butoxy hydride. Saturated odd and even numbered aldehydes were prepared by the ozonolysis-reduction of 1-alkenes. Ozonides were hydrogenated with a Lindlar catalyst or reduced with dimethyl sulfide. Several diols, including 1,3-propanediol and ethylene glycol, wer...

Various ketones, esters, amides, and thioesters add in high yield to dimethyl acetals in the presence of silyl trifluoromethanesulfonates and an amine base. Acetals derived from aryl, unsaturated, and aliphatic aldehydes are all effective substrates. The reaction proceeds in a single reaction flask, with no purification of the intermediate enol silane necessary.

The metabolism of the stereomeric cyclic glycerol acetals of [1-(14)C]hexadecanal was studied in myelinating rat brain. It was found that the four isomers, cis- and trans-2-pentadecyl-5-hydroxy-1,3-dioxanes and cis- and trans-2-pentadecyl-4-hydroxymethyl-1,3-dioxolanes, were utilized by the tissue at different rates. The acetals were primarily metabolized via a ring-opening mechanism leading to...

A new direct conversion of O,O-acetals to esters via O,P-acetal intermediates was developed. The regioselective cleavage of unsymmetrical cyclic acetals occurred to give the more crowded esters as single isomers.