Triarylmethane Dyes for Artificial Repellent Cotton Fibers.

Families of new hydrophobic and/or oleophobic triarylmethane dyes possessing long hydrocarbon or polyfluorinated chains have been prepared. When covalently grafted on to cotton fabric, these dyes give rise to a new type of colored superhydrophobic fibers.

An alternative to the classical α-arylation: the transfer of an intact 2-iodoaryl from ArI(O2CCF3)2.

The α-arylation of carbonyl compounds is generally accomplished under basic conditions, both under metal catalysis and via aryl transfer from the diaryl λ(3)-iodanes. Here, we describe an alternative metal-free α-arylation using ArI(O2CCF3)2 as the source of a 2-iodoaryl group. The reaction is applicable to activated ketones, such as α-cyanoketones, and works with substituted aryliodanes. This formal C-H functionalization reaction is thought to proceed through a [3,3] rearrangement of an iodonium enolate. The final α-(2-iodoaryl)ketones are versatile synthetic building blocks.

Diastereoselective additions of titanium enolates from N-glycolyl thiazolidinethiones to acetals.

The stereochemical outcome of the Lewis acid-mediated glycolate addition of the titanium enolates from protected N-hydroxyacetyl-4-isopropyl-1,3-thiazolidine-2-thiones to dimethyl and dibenzyl acetals depends on the hydroxyl protecting group. Particularly, the pivaloyl protected glycolate derivative provides the reluctant anti adducts in high yields and diastereomeric ratios, which can be isolated and further converted in enantiomerically pure form to ß-methoxy or ß-benzyloxy α-pivaloyloxy carbonyl fragments in a straightforward manner.

Geometry-selective synthesis of E or Z N-vinyl ureas (N-carbamoyl enamines).

N-Vinyl ureas are emerging as a valuable class of compounds with both nucleophilic and electrophilic reactivity. They may be made by capturing the enamine tautomer of an imine with an isocyanate, a reaction which in general leads to the E isomer of the vinyl urea. Deprotonation of such a vinyl urea, or of an allyl urea, generates a dipole stabilized Z-allyl anion which may be protonated to return the Z-vinyl urea. Isomerization of an allyl urea with a Ru complex provides an alternative route to E-vinyl ureas.

New approach to the stereoselective synthesis of tertiary methyl ethers.

The Lewis acid-mediated addition of titanium enolates from 1 to dimethyl ketals of aliphatic methyl ketones followed by removal of the chiral auxiliary furnishes enantiomerically pure derivatives containing a tertiary methyl ether and a contiguous stereocenter in a straightforward manner.