Search

A general strategy for the synthesis of arylthio cyclopropyl carbaldehydes and ketones via a Brønsted acid catalyzed arylthiol addition/ring contraction reaction sequence has been exploited. The procedure led to a wide panel of cyclopropyl carbaldehydes in generally high yields and with broad substrate scope. Mechanistic aspects and synthetic applications of this procedure were investigated. [ABSTRACT FROM AUTHOR]

We describe a photochemical reaction using two starting materials, a cyclopent-2-enone and an alkene, which are transformed in a controlled manner via the initial [2+2]- photocycloaddition adducts into cyclobutene aldehydes (conveniently trapped as stable acetals) or unprecedented angular tricyclic 4:4:4 oxetane-containing skeletons. These compounds are formed through tandem or triple cascade photochemical reaction processes, respectively. Small libraries of each compound class were prepared, thus suggesting that this photochemistry approach opens new opportunities for synthesis design and for widening molecular diversity. [ABSTRACT FROM AUTHOR]

An original synthetic protocol has been developed for the preparation of highly functionalized tryptamines from 2-hydroxycyclobutanone and secondary arylamines via a solvent-free Brønsted acid catalysed two-step reaction sequence. [ABSTRACT FROM AUTHOR]

The oxidation of organosulphides catalysed by hydrogen bonding donors derived from aminotetrazole has been studied. The oxidation reaction was performed in a H2O solution using H2O2 as a versatile, green and chemoselective new approach to sulphoxides. Sulphoxide compounds are obtained in high yields and excellent selectivity through a new and easy to perform oxidation protocol. Aminotetrazole derivatives can be recycled by filtration and reused several times without expensive purification procedures. [ABSTRACT FROM AUTHOR]

A catalytic enantioselective synthesis of α-arylaminocyclobutanones from racemic α-hydroxycyclobutanone and a selection of N-alkylanilines has been established, via a tandem condensation/keto-enol tautomerization process reminiscent of the Amadori and Heyns rearrangements. [ABSTRACT FROM AUTHOR]

An overview of the most important synthetic strategies currently available for the preparation of cyclopent-2-enones is presented and illustrated with recent applications. [ABSTRACT FROM AUTHOR]

The stereoselective solvent-free organocatalyzed aldol reaction of 2-hydroxycyclobutanone with a selection of aromatic aldehydes has been investigated. Using L-threonine (20 mol%), deracemized aldol adducts featuring a chiral quaternary center were obtained in yields up to 72%, with syn selectivity up to 85:15 and ee up to 84%. The title compound has markedly superior reactivity to other α-hydroxy ketones. [ABSTRACT FROM AUTHOR]

Abstract: α-Phenoxy- and phenylthio-ketones have been explored as donors and acceptors in organocatalytic aldol reactions. Our studies have revealed effective methodologies for accessing structurally varied and enantiomerically enriched secondary and tertiary phenylthio- and phenoxy-aldols, expanding the scope and potential synthetic utility of organocatalytic direct aldol reactions. [Copyright &y& Elsevier]

Abstract: The selective oxidation of aromatic and aliphatic organosulfides with H2O2/H2O catalyzed by metal free ammonium salts has been explored. Reactions were performed using 2.5–5mol% of catalyst loadings, isolating the corresponding sulfoxides in good to excellent yields (75–93%) and high selectivity. [Copyright &y& Elsevier]

Starting from cyclobutanones and tertiary cyclobutanols several new chromenes containing a cyclobutane ring have been prepared by acid catalyzed intramolecular alkylation of an oxygen-carrying aromatic ring. Interestingly one of the cyclobutanols leads to 3-[(4-methoxyphenoxy)methyl]-2,2,3-trimethylcyclopentanone that is a precursor in the synthesis of the carotenoid pigment capsorubin. [Copyright &y& Elsevier]

Review: 164 refs. [ABSTRACT FROM AUTHOR]