Oxidative sulfonylarylation of strained C–C σ-bonds for the synthesis of 3-spirocyclic oxindoles initiated by insertion of sulfur dioxide

Abstract

The development of difunctionalisation reactions of C–C σ-bonds remains a long-standing challenge, but very significant in synthetic chemistry, considering that C–C σ-bonds are ubiquitous in organic molecules. However, there are...

Facile synthesis of alkylphosphonates from 4-alkyl-1,4-dihydropyridines via photoinduced formal deformylative phosphonylation

“…Alternatively, as pioneered by Nishibayashi and Molander, 12,13 a more practical, two-step approach was developed, which takes advantage of the convenient synthesis of 4-alkyl-1,4-dihydropyridines (DHPs) from aldehydes. Given the extremely mild conditions for the exclusive generation of alkyl radicals through oxidative fragmentation of DHPs, especially under photocatalysis, 14 a great number of C(sp 3 )-centered radical transformations via formal deformylation of aliphatic aldehydes were achieved, including the construction of C–C, 15 C–N, 16 C–X (X = I, Br, Cl), 17 and C–S/Se 18 bonds. However, there have been no reports to date on deformylative C(sp 3 )–P(O) bond formations.…”

Oxidative Difunctionalization of N-Aryl Bicyclobutyl Amides with Aldehydes: Divergent Synthesis of Acylated and Alkylated 3-Spirocyclobutyl Oxindoles

“…Recently, our group developed a radical approach for the oxidative cyclization of N -aryl BCB-amides, that is, a visible-light-induced alkylarylation of BCBs with α-carbonyl alkyl bromides and a sulfonylarylation of BCBs with 4-alkyl 1,4-dihydropyridines (DHPs) and Na 2 S 2 O 5 (Scheme c), which offers a new synthetic toolkit toward functionalized 3-spirocyclobutyl oxindoles . To further expand the applications of this strategy in difunctionalization of BCBs, we envisioned the possibility of developing a new dicarbofunctionalization reaction of N -aryl BCB-amides with readily available aldehyde feedstocks .…”