The application potential of primary amine catalysts in the context of Mannich reactions of aldehydes with ketimines is exemplified by isatin-derived ketimines and cyclic trifluoromethyl ketimines. Primary amine catalysts exhibit either unusual stereoselectivity or reactivity, which is not observable with secondary amine catalysts. Moreover, reversal of diastereofacial selectivity between primary and secondary amine catalysts is disclosed. These new reactions provide useful methods for the syntheses of chiral 3-substituted 3-amino-2-oxindoles and dihydroquinazolinones bearing a trifluoromethylated quaternary stereocenter. The synthetic utility of the reactions is demonstrated through the formal synthesis of AG-041R and DPC 083 and the total synthesis of (-)-psychotriasine.

A stereoselective gold(I)‐catalyzed vinylcyclopropanation of alkenes has been developed. A gold‐coordinated cationic vinyl carbene species, readily generated via a rearrangement of the ethylenedithioacetal of propargyl aldehyde, reacts with a wide range of alkenes to afford thio‐substituted vinylcyclopropanes. The gold‐catalyzed vinyl cyclopropanation proceeds under mild conditions at room temperature and is generally selective for the formation of cis‐substituted cyclopropanes. The reaction allows the formal introduction of a “naked” vinyl carbene, by subsequent chemoselective hydrodesulfurisation of the ethylenedithio‐bridge. The synthetic utility of the new method is demonstrated by a short, racemic formal synthesis of the alkaloid cephalotaxin, hinging on a key vinyl cyclopropane‐cyclopentene rearrangement.

DedicatedtoP rofessor Dieter Endersont he occasion of his70th birthday.Supporting information for this article can be found under:http://dx.Abstract: Thef irst enantioselective conjugate additions of problematic aromatic ketones and acetone to nitrodienynes have been achieved by employing ac hiral multifunctional primary amine catalyst recently developed by us.T he reactions tookp lace in a1 ,4-manner. Furthermore,b yu tilizing the resulting chiral functionalized 1,3-enynes as as tarting point, we have developed unprecedented p-toluenesulfonic acid-catalyzed tandema nnulations, which allow the efficient ands elective constructiono fv arious synthetically useful cyclic1 ,5-diketones (R = Ar) and dienones (R = Me).

An efficient cobalt-catalyzed C–H acetoxylation of phenols has been developed by using PIDA (phenyliodine diacetate) as a sole acetoxy source to synthesize pyrocatechol derivatives for the first time. The key feature of this method is the use of earth-abundant metal cobalt as the green and inexpensive catalyst for the acetoxylation of C­(sp2)–H bonds under neutral reaction conditions. Furthermore, the gram-scale reaction and late-stage functionalization demonstrated the usefulness of this method.

The application potential of primary amine catalysts in the context of Mannich reactions of aldehydes with ketimines is exemplified by isatin‐derived ketimines and cyclic trifluoromethyl ketimines. Primary amine catalysts exhibit either unusual stereoselectivity or reactivity, which is not observable with secondary amine catalysts. Moreover, reversal of diastereofacial selectivity between primary and secondary amine catalysts is disclosed. These new reactions provide useful methods for the syntheses of chiral 3‐substituted 3‐amino‐2‐oxindoles and dihydroquinazolinones bearing a trifluoromethylated quaternary stereocenter. The synthetic utility of the reactions is demonstrated through the formal synthesis of AG‐041R and DPC 083 and the total synthesis of (−)‐psychotriasine.