We describe the first example of Rh-catalyzed intermolecular C-alkylation of cyclic 1,2-diketones using simple terminal olefins as alkylating agents. Aminopyridine is employed as a recyclable directing group. First, it reacts with ketones to give enamines and delivers Rh to activate the vinyl C-H bonds in the same pot; second, it can be cleaved off and recovered via hydrolysis. A broad range of olefins can be utilized as substrates, including aliphatic, aromatic olefins and vinyl esters. The efficiency of this method is also demonstrated in the synthesis of a natural flavoring compound, 3-ethyl-5-methyl-1,2-cyclopentadione (one-pot 53% yield vs a previous four-step route 16% yield from the same starting material). This work is expected to serve as a seminal study toward catalytic ketone α-alkylation with unactivated olefins.

A unique strategy to synthesize β-alkenylated α-enamino-ketones via catalytic C-H/alkyne coupling is described. The slow addition of alkyne substrates and the use of NaI as an additive play key roles in controlling the alkyne insertion. Replacement of the pyridyl group with carbamates was also developed. This method allows for rapid synthesis of highly functionalized vinyl-substituted enamino-ketones.

Screening of a variety of ligands and reaction conditions for the copper-catalyzed cross-coupling of alkynyl bromides with pyrroles, reveals that the use of the phenanthroline ligand 4,7-dimethoxy-1,10-phenanthroline affords a range of ynpyrroles in good to moderate yields. Furthermore, the utility of these ynpyrroles is demonstrated in the preparation of a series of pyrrolo[2,1-c][1,4]oxazin-1-ones and a formal total synthesis of the pyrrole natural product peramine.

A copper-catalyzed N-alkynylation of pyrrole and a gold-catalyzed spiroketalization were key steps in the total synthesis of the pyrrole spiroketal alkaloid shensongine A. The preparation of this alkaloid is concise and amenable to the rapid synthesis of a diverse library of compounds.

Catalytic Intermolecular C-Alkylation of 1,2-Diketones with Simple Olefins: A Recyclable Directing Group Strategy. -Rhodium-catalyzed α-alkylations of cyclic 1,2-diketones via reaction of 2-pyridyl-substituted enamides are developed. The process can be combined with enamine formation in one-pot. -(WANG, Z.; REINUS, B. J.; DONG*, G.; J. Am. Chem. Soc. 134 (2012) 34, 13954-13957, http://dx.doi.org/10.1021/ja306123m ; Dep. Chem. Biochem., Univ. Tex., Austin, TX 78712, USA; Eng.) -Mais 09-057