Iodine(III)-mediated halogenations of acyclic monoterpenoids

Abstract

Five different halofunctionalizations of acyclic monoterpenoids were performed using a combination of a hypervalent iodine(III) reagent and a halide salt. In this manner, the dibromination, the bromo(trifluoro)acetoxylation, the bromohydroxylation, the iodo(trifluoro)acetoxylation or the ene-type chlorination of the distal trisubstituted double bond occurred with excellent selectivity and moderate to good yields.

Synthesis of Cyclic N‐Hydroxylated Ureas and Oxazolidinone Oximes Enabled by Chemoselective Iodine(III)‐Mediated Radical or Cationic Cyclizations of Unsaturated N‐Alkoxyureas

“…In order to broaden the range of substrates that could be attainable by a direct cyclization, we wished to develop a reaction following a specific blueprint: avoiding the use of transition metals, no heating and installing a linchpin for further derivatizations. Based on our previous studies on hypervalent iodine(III) [19][20][21][22][23][24] -mediated halogenations, [25][26][27][28] and in particular modular halocyclizations, [29,30] we chose to focus on the bromocyclization of unsaturated N-oxyureas (5, Scheme 2). These substrates are challenging in terms of regio-and chemo-selectivity.…”

Rapid Oxidation Indoles into 2‐Oxindoles Mediated by PIFA in Combination with n‐Bu4NCl ⋅ H2O

“…We attempted to prepare the ammonium‐complexed halogen(I) species following the procedure reported by Toth, [10a] but a UV‐absorbing yellow solid was obtained; its structure is proposed to be 16 or its polymer (Figure 3A) based on NMR spectroscopy, HRMS, and its ability to chlorinate a monoterpenoid [10o] (Figure 3B) and indole (Figure 3C, left). When PIFA and n ‐Bu 4 NCl ⋅ H 2 O were replaced with 16 , oxindole product 11 a was produced in 73% yield under otherwise standard conditions (Figure 3C, right).…”

Alkene Difunctionalization Using Hypervalent Iodine Reagents: Progress and Developments in the Past Ten Years

“…Lastly, Cariou and coworkers recently demonstrated a chemodivergent, tunable, and selective method for bromofunctionalization of polyprenoids (Scheme 34) [107,108]. Depending on the combination of a hypervalent iodine source, inorganic salt, solvent, and temperature, the reaction produced selective dibromination, oxy-bromination, and bromocyclization reactions.…”