Multiple classes of commercially important auxin herbicides have been discovered since the 1940s including the aryloxyacetates (2,4-D, MCPA, dichlorprop, mecoprop, triclopyr, and fluroxypyr), the benzoates (dicamba), the quinoline-2-carboxylates (quinclorac and quinmerac), the pyrimidine-4-carboxylates (aminocyclopyrachlor), and the pyridine-2-carboxylates (picloram, clopyralid, and aminopyralid). In the last 10 years, two novel pyridine-2-carboxylate (or picolinate) herbicides were discovered at Dow AgroSciences. This paper will describe the structure activity relationship study that led to the discovery of the 6-aryl-picolinate herbicides Arylex™ active (2005) and Rinskor™ active (2010). While Arylex was developed primarily for use in cereal crops and Rinskor is still in development primarily for use in rice crops, both herbicides will also be utilized in additional crops.

An unusually high yielding fluorination of aminopyralid (3) using F-TEDA (SELECTFLUOR (TM)) in warm water, followed by kinetic resolution (via iterative esterification/saponification) of the crude fluorination product with dry HCl in methanol produced pure ring-fluorinated pyridine 2 in an overall yield of 31% for the two steps. (C) 2009 Elsevier Ltd. All rights reserved.

A concise synthetic route to the carbocyclic core of the cornexistins is reported. The route is highlighted by a Diels-Alder cycloaddition/oxidative cleavage strategy to generate the central highly functionalized nine-member ring. A silyl-tethered ring-closing metathesis strategy is utilized to control trisubstituted alkene geometry.

While 8′-trifluoromethyl ABA (2a) was known to be one of the most active and stable analogs tested in assays for ABA-like activity, a thorough evaluation of its biological properties was limited by compound availability. The current synthesis, which includes the preparation of a previously unknown key intermediate 2-methyl-2-trifluoromethyl-1,4-cyclohexanedione-mono ethylene ketal (18), has been accomplished in 14 steps and 3% yield. The key fluorinated ketal intermediate 18 was prepared in six steps and 20% yield.

Syntheses of naturally occurring organophosphonates and organophosphinates are reviewed. Review contains 161 refs.