The first total synthesis of the dimeric berberine alkaloid ilicifoline (ilicifoline B) is reported. Its carbon skeleton is constructed from ferulic acid, veratrole, and methanol. The synthesis reported herein employs starting materials solely derived from wood. The natural product is thus constructed entirely from renewable resources. The same strategy is applied to a formal total synthesis of morphinan alkaloids. The use of wood-derived building blocks (xylochemicals) instead of the conventional petrochemicals represents a sustainable alternative to classical synthetic approaches.

A series of Lewis acid-base pairs containing sterically demanding carbenes were investigated for hydrogen activation that could potentially be reversible for use in hydrogen storage applications. When electron-rich boranes are employed as electrophiles, the imidazolium cation is reduced to a 2H-imidazoline (aminal). The aminals were synthesized independently by reduction of imidazolium cations with strong reducing agents. Carbocations were also found to act as electrophiles for hydrogen activation. Preliminary results revealed that it is possible to reduce an alcohol to an alkane using hydrogen gas as a reducing agent in these systems. Finally, it was demonstrated that a transition metal can be used as an electrophile to activate hydrogen through heterolytic cleavage. 1 3 4 2 Scheme 1. A carbene-borane Lewis pair for hydrogen activation.

Gripping ligands: A series of fluoroalkoxy‐functionalized imidazol‐2‐ylidene ligands were synthesized by the alkylation of a range of commercially available azoles with hexafluoroisobutylene oxide. The deprotonation of these species with a strong base cleanly generated the free carbenes, which acted as tridentate chelating ligands (see scheme).

The formation of phosphinidenoid complex salts having weakly coordinating cations (WCCs) is reported via treatment of P-functional phosphane complexes with N,N’-di-tert-butyl imidazol-2-ylidene or a P4-t-Bu phosphazene base. The thermal stability of phosphinidenoid complex salts is dependent upon the P–X substituents and the nature of the WCC. The complexes were characterized by multinuclear NMR spectroscopy and confirmed by single-crystal X-ray structure.

The interaction of electron rich imidazol-2-ylidenes with electron poor cyanocarbons is reported. Contrary to previous reports of electron transfer products from imidazol-2-ylidenes and tetracyanoethylene, a number of ring forming cyanocarbon ring structures are isolated and characterized. Cyanation of the imidazole ring was explored by the addition of cyanogen chloride to imidazol-2-ylidenes. * Prof. Dr. A. J. Arduengo, III Fax: +1-205-348-4704 E-Mail: aj@ajarduengo.net [a]