When cyclopropenes meet gold catalysts

• Frédéric Miege,
• Christophe Meyer and
• Janine Cossy

Beilstein J. Org. Chem. 2011, 7, 717–734, doi:10.3762/bjoc.7.82

• undergo subsequent ring-opening to produce an organogold species that can be viewed as a hybrid between a gold-stabilized allylic carbocation B and a gold carbene C. The organogold carbenoid species generated by the ring-opening of cyclopropenes can participate in a variety of reaction types such as

• ) carbenoid complexes, Toste et al. highlighted the importance of the substitution pattern and the ligands (Scheme 4). Interestingly, DFT calculations were carried out for organogold species that can actually be generated by ring-opening of cyclopropenes, and therefore the authors examined experimentally the

• reflux [33][38]. These reactions appear to constitute the first examples of intramolecular olefin cyclopropanation promoted by a silver carbenoid generated by ring-opening of a cyclopropene. We envisioned that the gold carbene resulting from the ring-opening of appropriately substituted cyclopropenes

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

Beilstein J. Org. Chem. 2009, 5, No. 33, doi:10.3762/bjoc.5.33

• insertion The laboratory of G.A. Sulikowski proposed a synthesis of 1,2-aziridinomitosenes [106][107] using as key transformations a Buchwald–Hartwig cross-coupling [108][109][110] and a chemoselective intramolecular carbon-hydrogen metal-carbenoid insertion reaction (Scheme 39). The chiral pyrolidine 136

Synthesis of highly substituted allenylsilanes by alkylidenation of silylketenes

• Stephen P. Marsden and
• Pascal C. Ducept

Beilstein J. Org. Chem. 2005, 1, No. 5, doi:10.1186/1860-5397-1-5

• carbenoid-based reagents. Introduction Allenylsilanes are versatile intermediates for organic synthesis.[1][2] They have two main modes of reactivity: firstly, as propargyl anion equivalents in thermal [3][4] or Lewis acid-mediated [5][6] addition to carbonyls, acetals and imines, and secondly as three

• problem, it gave us the encouragement to screen other titanium carbenoid-based methylenating reagents. The Petasis reagent (dimethyltitanocene) [31][32] was our next choice, and we were pleased to find that it afforded modest to excellent yields of the allenylsilanes in reaction with most of the ketene