Steven T. Diver

Ethylene metathesis of sulfur-containing alkynes

Abstract Enyne metathesis of sulfur-containing alkynes and ethylene has been achieved. High yields were obtained by use of thiol esters in the alkyne partner for the cross metathesis with ethylene. The necessary reactivity and functional group compatibility were achieved through the use of the Grubbs’ second generation benzylidene carbene catalyst.

Tandem dienyne cross-metathesis/ring-closing metathesis

Abstract Tandem enyne cross-metathesis/ring-closing metathesis between terminal alkynes and 1,5-hexadiene has been demonstrated using the 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene-substituted ruthenium benzylidene complex. Synthesis of 2-substituted 1,3-cyclohexadienes using this one step tandem reaction is reported. In addition, metathesis products were subjected to [4+2] cycloaddition with N -methylmaleimide yielding the corresponding cycloadducts in one synthetic step.

A General, Modular Approach to a New Family of Amine-Substituted Arylboronic Acid Saccharide Chemosensors

A general synthetic approach towards a class of water-soluble, high quantum yield fluorescent saccharide reporters using 6-morpholinonaphthalene-2-yl boronic acid as an illustrative case is reported. The strength and flexibility of this approach, which utilizes the Buchwald–Hartwig cross-coupling reaction, is further underscored by the preparation of several additional aminonaphthalenes in excellent yield, including one that bears a chiral unit.

Organometallic chemistry: catalyst takes control to heart.

Some transition-metal catalysts control organic reactions so that, given a choice of two mirror-image products, only one forms. The metal atom in these catalysts has been ignored as a source of control — until now. Alkene metathesis (also called olefin metathesis or transalkylidenation) is an organic reaction widely used to synthesize products including medicines, polymers and fuels. Its importance was recognized in 2005, when Yves Chauvin, Robert Grubbs and Richard Schrock shared the Nobel prize for work on metathesis. A new class of molybdenum-based chiral catalyst, capable of initiating alkene metathesis with exceptional efficiency and enantioselectivity, is reported in this issue. The new catalysts bear a stereogenic metal centre and carry only monodentate ligands. Their effectiveness was demonstrated in an enantioselective synthesis of the Aspidosperma alkaloid, quebrachamine, via a metathesis reaction that cannot be promoted by any of the previously reported catalysts.