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The ability of certain organometallic reagents to react via 1,2-or 1,4-addition to an α,β-unsaturated ketone is a fundamental example of regioselectivity at the second-year undergraduate organic level. The following two experiments were designed to demonstrate this preference by exploiting carvone as an inexpensive chiral, nonracemic substrate. The first, intended for a typical undergraduate audience, makes use of phenylmagnesium bromide; the second calls for the manufacture of lithium dimethylcuprate from a stock solution of methyl lithium and copper(I) iodide and is envisioned to be carried out by upper-division students. Importantly, due to the chiral nature of carvone, these addition reactions are highly stereoselective and will provide an opportunity for students to revisit stereochemistry. Also discussed are several thoughts on assessment of student learning as well as an easy to adopt protocol that details reaction setup, aqueous workup, purification, waste management, and the analysis of products using 1 H NMR spectroscopy.

The use of trimethylsilyl trifluoromethanesulfonate as a mild means to unite epoxy-carvone silyl ethers with anisole derivatives to yield products that are structurally similar to the CBD scaffold is reported. Importantly, unlike related methods, this process can utilize both epoxy-carvone diastereomers and does not require the use of air/moisture-sensitive organometallic reagents. Several examples of aryl nucleophiles as well as mechanistic insight based on in silico computational analysis are presented.

The first asymmetric total synthesis of C(9)-S-(+)-taumycin A is now reported using an approach that targeted both C(9) diastereomers concurrently. To facilitate this work, we called upon the symmetrical nature of a C(5)−C(13) side-chain intermediate and exploited orthogonal protecting groups as a tactic to access both stereoisomers from a single chiral, nonracemic intermediate. In addition to our successful approach, several minor detours that helped refine our strategy and a detailed analysis of 1 H NMR data will be discussed. Select compounds included in this work were screened against the NCI60 cell line panel and displayed modest growth inhibition activity.

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