α-Bromodiazoacetamides – a new class of diazo compounds for catalyst-free, ambient temperature intramolecular C–H insertion reactions

• Åsmund Kaupang and
• Tore Bonge-Hansen

Beilstein J. Org. Chem. 2013, 9, 1407–1413, doi:10.3762/bjoc.9.157

• cycloaddition, ylide formation, cyclopropanation and C–H insertion reactions [1][2][3]. A generally useful modification of diazo compounds is the substitution of the α-hydrogen for an electrophile. This substitution can be effected in the presence of a base or starting from the metalated diazo compound, and

• interpreted from Table 1, the dominant reaction pathway in the high-yielding reactions (Table 1, entries 2–3), is apparently the intramolecular C–H insertion to form a β-lactam. The preferential formation of intramolecular products from N,N’-disubstituted diazoacetamides, as compared to diazoacetates has

• which the α-substituent on the carbene carbon varies (see below). The α-phenyl analogue of β-lactam 5b has previously been prepared by carbene C–H insertion. In these reports, the base-promoted decomposition of a hydrazone and subsequent thermolysis of the diazo compound in, e.g., toluene under reflux

Metal–ligand multiple bonds as frustrated Lewis pairs for C–H functionalization

• Matthew T. Whited

Beilstein J. Org. Chem. 2012, 8, 1554–1563, doi:10.3762/bjoc.8.177

• the types of reactivity discussed thus far, there are several distinct routes to the functionalization of C–H (or E–H) bonds using metal–ligand multiply bonded FLPs. If C–H activation is effected by 1,2-addition across a M═E bond, then reductive elimination could result in a net C–H insertion of

Intramolecular hydroxycarbene C–H-insertion: The curious case of (o-methoxyphenyl)hydroxycarbene

• Dennis Gerbig,
• David Ley,
• Hans Peter Reisenauer and
• Peter R. Schreiner

Beilstein J. Org. Chem. 2010, 6, 1061–1069, doi:10.3762/bjoc.6.121

• Dennis Gerbig David Ley Hans Peter Reisenauer Peter R. Schreiner Institut für Organische Chemie, Justus-Liebig University Giessen, Heinrich-Buff-Ring 58, 35392 Giessen, Germany 10.3762/bjoc.6.121 Abstract The first C–H insertion of a hydroxycarbene species in the gas phase has been observed

• intermediate leading to the tautomeric formyl group. Thermochemical computations at M06-2X/cc-pVDZ in conjunction with a self-consistent solvent reaction field model support this suggested reaction pathway. Keywords: benzofuran; C–H-insertion; hydroxycarbene; singlet carbene; tunneling; Introduction

• existing signals, thereby verifying the complete absence of 5. Analysis of the IR spectrum showed that 8 was the main product instead. To confirm the C–H-insertion into the neighboring methyl group, to yield 2,3-dihydrobenzofuran-3-ol (8), a sample of 8 was prepared by the reduction of commercially

Mitomycins syntheses: a recent update

• Jean-Christophe Andrez

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

• of the indoline intermediate to the indole. The regioselectivity is in accord with the results of Adams who showed that the C–H bond with the highest electron density was the most likely to migrate during rhodium(II) mediated C–H insertion [113]. A related study assessed the possibility of

• circumventing this regioselectivity issue by exploiting the enantioselective intramolecular C–H insertion of diazoester 144 into a meso pyrrolidine using chiral catalyst 145. Unfortunately the reaction displayed low enantio- and diastereoselectivity, with the major isomer 146 having an ee of only 51% (Scheme 40