Ligand effects on dirhodium(II) carbene reactivities. Highly effective switching between competitive carbenoid transformations

Buchner and Beyond: Arene Cyclopropanation as Applied to Natural Product Total Synthesis

“…16 These studies have primarily utilized arenes bearing electron-releasing substituents, as electron-deficient arenes are typically poor substrates for arene cyclopropanation. 14,17 The interest in aryldiazobutanone substrates such as 14a is fueled in part by the large number of sesquiterpene natural products with bicyclo[5.3.0]decane core structures (e.g. 20, Scheme 4), to which this synthetic methodology provides a convenient entry.…”

Catalytic asymmetric C–H insertion reactions of α-diazocarbonyl compounds

“…70 In general, decreased reactivity has been observed for catalytic reactions with α-diazocarbonyls in the presence of carboxamidates, compared with the corresponding carboxylates, but higher selectivites are possible, making these complexes a popular catalytic choice for C-H insertion reactions. [71][72][73] Doyle's chiral rhodium(II) carboxamidate complexes were first reported for enantioselective cyclopropanation reactions in 1990. 74 These catalysts have since been much exploited and remain today the primary catalysts for enantioselective C-H insertion reactions of electronwithdrawing group-substituted carbenoids derived from diazoacetamides and diazoesters.…”

“…It is believed that aromatic C-H insertion reactions proceed via a mechanism of electrophilic addition of the rhodium(II) carbenoid carbon to the aromatic ring followed by 1,2-hydride migration to give the aromatic insertion product. 71,144 Therefore, elimination of this competing process may be achieved by attachment of an electron-withdrawing substituent at the para position of the aromatic ring. This was indeed found to be true and exclusive production of 110 was observed for the C-H insertion reaction of 108 (X = NO 2 ) in the presence of various rhodium(II) phthaloyl complexes (Table 24, entries b-e).…”

Microwave-Assisted Synthesis and Characterization of [Rh2(OAc)4(L)2] Paddlewheel Complexes: A Joint Experimental and Computational Study

“…In this regard, the rhodium acetate complex [Rh 2 (OAc) 4 ], I, has been recognized as (i) a valuable, stable, and easy-tohandle catalyst; and (ii) a linker in the synthesis of inorganic polymers and cages, II and III, respectively ( Figure 1) [9][10][11][12][13]. The number of reports involving I in the fields of biochemistry [14][15][16][17], catalysis [18][19][20], and bioorganometallic [21,22], inorganic [23][24][25][26], and organometallic chemistry [27][28][29] has been increased to an average of sixty papers per year in the last decade (according to SciFinder at 03-01-2017).…”

“…Later, the works independently published by Hubert et al among others showed the use of complex I as a catalyst for the cyclopropanation of olefins and allylic activation by diazo-esters [19,20,[27][28][29][31][32][33][34][35][36][37][38][39].…”