Regioselectively produced 2‐ and 3‐acetyl‐1‐(phenylsulfonyl)pyrroles can be reduced to the corresponding alcohols and subsequently dehydrated to afford N‐protected vinylpyrroles. These remarkably stable vinylpyrroles can then serve as heterodienes in [4 + 2] cycloaddition reactions with electron deficient dienophiles to afford tetrahydroindole derivatives.

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[formula: see text] Tamandarin A (1), a newly isolated natural product similar in structure to didemnin B (2), was shown to be somewhat more active in vitro than 2 against pancreatic carcinoma with an ED50 value 1.5 to 2 ng/mL. We report here the first total synthesis of 1. The key steps include a practical stereoselective synthesis of the Hiv-isostatine unit, high-yielding linear precursor formation, a successful macrocyclization, and coupling of the macrocycle with the side chain to afford tamandarin A (1).

Two efficient synthetic methods for preparation of 3-(trifluoromethyl)cyclobutane-1-carboxylic acid are reported starting from readily available 4-oxocyclobutane precursors. These cyclobutanones can be converted to their CF 3 carbinols upon treatment with TMSCF 3 and a fluoride source. The bis-carboxylate system 9 was deoxygenated by treatment of Bu 3 SnH and provided desired compound 1 upon decarboxylation. In the monocarboxylate system 15, the triflate could be efficiently eliminated; subsequent hydrogenation afforded cis-1. KEYWORDS: 3-(trifluoromethyl)cyclobutane-1-carboxylic acid, cyclobutane isostere of benzene, medicinal chemistry building blocks, base-mediated elimination of sterically hindered, electronically deactivated tert-CF 3 carbinol triflate