C(sp²)–H cyclobutylation of hydroxyarenes enabled by silver-π-acid catalysis: diastereocontrolled synthesis of 1,3-difunctionalized cyclobutanes

Abstract

A carbophilic silver Lewis acid catalyzes polar strain-release ring-opening of BCBs with hydroxyarenes to afford 1,1,3-trisubstituted cyclobutanes in high yields and excellent chemo- and diastereoselectivity.

Silver‐Catalyzed Dearomative [2π+2σ] Cycloadditions of Indoles with Bicyclobutanes: Access to Indoline Fused Bicyclo[2.1.1]hexanes**

“…scope was limited to N ‐protected indoles bearing an electron‐withdrawing group at the C2 or C3 position (Scheme 1c); [10d] (3) BCBs easily undergo silver catalyzed rearrangements to corresponding dienes by cleavage of the C−C edge bonds in BCBs. By contrast, direct activation of the central bond of BCBs by carbophilic silver catalysis is still scarce; [14c,15] (4) Besides these, the other problem that needs to be solved is how to suppress the side reactions including the competitive bicyclobutane‐to‐cyclobutene isomerization [11a] and the ring opening of BCBs, [16] and how to control the regioselectivity in the cycloaddition.…”

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

“…3 Among them, the cycloaddition reaction of BCBs with a diverse array of reaction partners has been widely reported, 4 which provides an efficient protocol for the construction of three-dimensional C(sp 3 )-rich cyclic frameworks with important physiochemical properties. In addition, polar addition reactions, 5 carbene insertion reactions, 6 and other reactions 7 have been well investigated.…”

Substituent Effects on the Equilibria between Cyclopropylcarbinyl, Bicyclobutonium, Homoallyl, and Cyclobutyl Cations

“…Recently, Anderson and Duarte reported on the acid-mediated rearrangement of bicyclobutane amides IX , forming cyclopropylcarbinyl or cyclobutane products X or XI , both in good diastereoselectivity, depending on slight changes in substitution on the cation XII . The electrophilic opening of strained bicyclobutanes, which generate BCB/CPC/CB cations, , have recently garnered a lot of attention for the formation of cyclobutanes and cyclobutenes. − …”