Direct Annulations toward Phosphorylated Oxindoles: Silver‐Catalyzed Carbon‐Phosphorus Functionalization of Alkenes

Interception of Cobalt‐Based Carbene Radicals with α‐Aminoalkyl Radicals: A Tandem Reaction for the Construction of β‐Ester‐γ‐amino Ketones

“…Similarly, the fact that compound 12 (a precursor to an organoradical species) was also a poor choice of substrate (Scheme S2 c) indicated that the b-ester-g-amino ketone is not formed by the reaction of the a-diazo reagent with the olefin followed by coupling with the amine. N-Methyl-N-phenylmethacrylamide (13), an efficient radical acceptor for the construction of oxindoles by homolytic aromatic substitu-tion, [11] was subjected to the standard conditions, and the corresponding oxindole 14 could be isolated, albeit in a low yield of 15 %, which indicated that the cobalt carbene radical had been intercepted with an a-aminoalkyl radical (Scheme S2d).…”

Arylphosphonylation and Arylazidation of Activated Alkenes

“…A similar normal secondary KIE (KIE = 1.3) was measured in an intramolecular experiment with [D]-5 a as the substrate (Scheme 4 b, c). [11,19] The presence of an alkyl group on the nitrogen atom generates a more nucleophilic amidyl radical (see Scheme 2 and Scheme 3 a), thus triggering a subsequent C(sp 2 ) À N bond formation. [17] Ph 2 P(O)H seems to be the key hydrogen source in these reactions, [18] whereas in the reaction with azide-transfer reagent 4, adventitious traces of water in the medium seem to be responsible for the formation of the NÀH bond (Scheme 4 d).…”

“…Following the pioneering work of Sharpless and co-workers, [1] alternative methods to enable the introduction of two functional groups across alkenes in a catalytic, regio-and stereocontrolled manner have been intensively studied. [10] In this context, phosphonyl [11] and azido [12] oxindoles have recently been described. In contrast, the carbo-and heterofunctionalization of alkenes involving the incorporation of arenes has been more limited and mostly restricted to the formation of oxindoles and related heterocycles.…”

A DFT study on the reaction mechanisms of phosphonation of heteroaryl N-oxides with H-phosphonates

“…Actually, the tricoordinated phosphite can bind strongly to the Pd (II) center with its lone electron pair [9]. Thus, stoichiometric and environmentally unfriendly oxidants, such as manganese [10,11], or silver salts [12,13] were often required, which would reduce the overall 'greenness' of the process and limit its widespread usage. Scheme 1.…”