Titanium-induced reductive coupling of carbonyls to olefins

Abstract

Active titanium metal, produced in a finely divided form by Feduction of Tic13 with either potassium or lithium, will reductively couple ketones and aldehydes to olefins. Although the intermolecular coupling works best when two identical carbonyls are coupled to a symmetrical product, unsymmetrical couplings can also be carried out in certain cases. The unsymmetrical coupling of a diaryl ketone with another partner is particularly efficient, and a mechanism to account for this is proposed. Intramolecular dicarbonyl coupling to form rings is also possible, and the combinaiion TiCls/Zn-Cu works best. Rings of size 4-16 and 22 are prepared in high yield. The nature of the active titanium metal is studied by scanning electron microscopy, and a mechanistic proposal accounting for all observed resulb is presented. It is believed that the coupling reaction occurs on the surface of the active titanium particle.

Poly(p-phenylene alkylene)s – A forgotten class of polymers

“…Thus, this methodology seems to be a suitable synthetic tool for the preparation of the present target polymers, although the coupling of aliphatic ethynylenes in polymer synthesis has received little attention in the past 30) . The McMurry reaction is a titanium-induced reductive coupling of two carbonyl compounds that was invented 101) and developed 102) in the seventies. The reducing agent is a low-valent titanium species, which can be prepared in situ by treatment of TiCl 3 or TiCl 4 with metals (e. g. zinc) or LiAlH 4 .…”

Conformers and Rotamers of (±)-trans-2,3-Bis(2-naphthyl)-15-crown-5 and -18-crown-6 and Their Alkali Metal Complexes

“…In these two crown ethers there is an 1-Naphthaldehyde was converted into (E)-2-naphthostilbene by the McMurry reaction [8] and subsequently oxidized additional conformational bias, namely the mutual rotation of the vicinal 1-naphthyl groups, a phenomenon which we by the catalytic Sharpless oxidation with OsO 4 /NMO [9] to give the racemic diol 3 whose (R,R) enantiomer was rehave previously investigated for the corresponding 2,3-dihydro crown ethers.…”

All‐cis‐1,4,7,10‐Cyclododecatetraen – Röntgen‐strukturanalyse und Photoelektronenspektrum

“…[A] und Winkel ["I, Standardabweichung in Klammern: Cl-C12 1.323(2), C3-C4 1.326(2), C&C7 1.325 (2). C9-C10 1.321 (2).…”

“…C7-C8 1.506 (2). C8-C9 1.503 (2). ClO-Cll 1.505(2), Cll-C12 1.495(2); C2-CI-Cl2 127.1(1), C2-C3-C4 127.5(1).…”