A convergent asymmetric synthesis of the antitumor antibiotic macbecin I has been achieved. Six of the seven stereogenic centers within the target structure were controlled using asymmetric aldol methodology, while the final stereogenic center was established through internal asymmetric induction. Fragment coupling was accomplished using a mild, titanium tetrachloride mediated aldol reaction. T...

A versatile and general catalytic strategy has been developed for the α-arylation of phosphonoacetates utilizing parallel microscale experimentation. These α-substituted phosphonoacetates are widely useful, notably as substrates in the Horner-Wadsworth-Emmons-type olefinations. However, the current routes to these products involve harsh conditions, limiting the variety of functionality. The rep...

Functionalized distyrylbenzene analogs and , bearing a tris-(2-pyridylmethyl)amine-based receptor for Zn(2+), were synthesized by a Horner-Emmons-Wittig coupling reaction. It has been found that Zn(2+) complexation induces changes in the linear absorption spectrum that enhance a nonlinear sequential two-photon absorption of nanosecond pulses at 532 nm. This absorption was also found to depend o...

Transpacific pollution transport during INTEX-B: spring 2006 in context to previous years G. G. Pfister, L. K. Emmons, D. P. Edwards, A. Arellano, G. Sachse, and T. Campos National Center for Atmospheric Research, Boulder, CO, USA NASA Langley Research Center, Hampton, VA, USA Received: 12 August 2009 – Accepted: 12 August 2009 – Published: 31 August 2009 Correspondence to: G. G. Pfister (pfist...

Several variants of reductive ozonolysis, defined here as the in situ generation of aldehydes or ketones during ozonolytic cleavage of alkenes, are demonstrated to work effectively in tandem with a number of C-C bond-forming reactions. For reactions involving basic nucleophiles (1,2-addition of Grignard reagents, Wittig or Horner-Emmons olefinations, and directed aldol reactions of lithium enol...

Substituted 3-(fluoroacyloxy)quinoline-2,4(1H,3H)-diones including 3-(fluoroiodoacetoxy) derivatives react with triethyl phosphite to afford either the product of the Perkow reaction or the corresponding 4-ethoxyquinolin-2(1H)-one. In both reactions, the fluorocarboxylate anion acts as the first observed leaving group. This observation restricts the application of the intramolecular Horner-Wads...

An efficient approach for the introduction of 3-acyl side chain groups onto a core tetramate system, which are suitable for further manipulation by nucleophilic displacement or Horner-Wadsworth-Emmons coupling, provides access to a diverse library of substituted tetramates related to two distinct classes of natural products, equisetin and pramanicin. Assessment against S. aureus and E. coli ind...