Enantioselective iodolactonization to prepare ε-lactone rings using hypervalent iodine

Abstract

We describe the first highly enantioselective 7-exo-trig iodolactonizations of conformationally unbiased ε-unsaturated carboxylic acids, effected by an unusual combination of a bifunctional BAM catalyst, I2, and I(iii) reagent (PhI(OAc)2:PIDA).

Recent Advances in Catalytic Asymmetric Syntheses of Functionalized Heterocycles via Halogenation/Chalcogenation of Carbon‐Carbon Unsaturated Bonds

“…Using the bifunctional BAM catalyst 37, diverse chiral ɛ-lactones containing allcarbon quaternary chiral centers were obtained with good yields (up to 90%) and good to excellent enantioselectivities (up to 96% ee). [73]…”

“…The combination of PIDA/I 2 generating the reactive iodonium species is essential to this transformation. Using the bifunctional BAM catalyst 37 , diverse chiral ϵ‐lactones containing all‐carbon quaternary chiral centers were obtained with good yields (up to 90%) and good to excellent enantioselectivities (up to 96% ee) [73] …”

PhI(OAc)2-Promoted Regioselective Cycloaddition of N-Aminopyridinium Ylides with Electron-Deficient Alkenes

“…[1][2][3] In this context, the most common application of hypervalent iodine reagents is to serve as oxidants for various oxidative transformations, which delivers high synthetic practicability. [4][5][6][7][8][9] Recently, the scope of this region has been extended to visible-light photoredox catalysis, [10][11][12] asymmetric synthesis, 13,14 and transition-metal catalysis, [15][16][17] promoting the development of new catalytic modes. For example, in 2018, the group of Liu demonstrated a novel ring-expansion protocol for the construction of medium-sized lactams from cyclic ketones, using benziodoxole acetate (BI-OAc) as the oxidant.…”

Re2O7/HReO4 Mediated Intramolecular Hydroacyloxylation of Unactivated Alkenes: A Dual Hydrogen-Bonding Effect

“…Lactones, notably γ-lactones and δ-lactones (Scheme ), have widespread applications as agrochemicals, fragrances, drugs, precursor for polymers, food additives, etc . Tremendous synthetic efforts have been dedicated toward the development of new and more efficient protocols for their preparations, among which the intramolecular hydroacyloxylation reaction of an olefinic acid is, arguably, one of the most effective and atom-economical processes. Various catalysts have been reported to promote this transformation, including Brønsted acids, Lewis acids, and transition metals …”