Iodane‐Guided ortho C−H Allylation

Abstract

Ametal-free C À Hallylation strategy is described to access diverse functionalized ortho-allyl-iodoarenes.T he method employs hypervalent (diacetoxy)iodoarenes and proceeds through the iodane-guided "iodonio-Claisen" allyl transfer.T he use of allylsilanes bearing electron-withdrawing functional groups unlocks the functionalization of ab road range of substrates,i ncluding electron-neutral and electronpoor rings.T he resulting ortho-allylated iodoarenes are versatile building blocks,w ith examples of downstream transformation including ac oncise synthesis of the experimental antimitotic core of Dosabulin. DFT calculations shed additional light on the reaction mechanism, with notable aspects including the aromatic character of the transition-state structure for the [3,3] sigmatropic rearrangement, as well as the highly stereoconvergent nature of the trans-product formation.

SVI–C Linkage for Allylsulfonximines via BF3-Mediated Allylation

“…Therefore, 1a was first triggered via the activator BF 3 , followed by the Si−C bond activation in the SuFEx process. 13,20 The accumulated findings substantiated a plausible mechanism, as depicted in Scheme 3C. Initially, the interaction of two molecules of BF 3 •OEt 2 with 1a promoted the action of S−F bonds, forming highly electrophilic active intermediate Int-II.…”

“…By contrast, the activation of allyltrimethylsilane 2a posed a formidable challenge, requiring a significantly higher free energy barrier of 32.1 kcal/mol via a six-membered ring transition state Ts-A . Therefore, 1a was first triggered via the activator BF 3 , followed by the Si–C bond activation in the SuFEx process. , The accumulated findings substantiated a plausible mechanism, as depicted in Scheme C. Initially, the interaction of two molecules of BF 3 ·OEt 2 with 1a promoted the action of S–F bonds, forming highly electrophilic active intermediate Int-II .…”

Morita-Baylis-Hillman Reaction Inspired [3,3]-Rearrangement of Aryl Iodanes with α,β-Unsaturated Oxazolines

“…4A). The remaining iodide atom allowed for elaborating alkenes with a boryl group (7) or vinyl ester moieties (8a and 8b), and incorporating an alkynyl group into phenyl ring (9a and 9b) (Fig. 4B).…”

“…[5][6] The subsequent [3,3]-rearrangement occurs spontaneously leading to synthetically appealing ortho-functionalized aryl iodides. In the past three decades, an array of nucleophiles such as allyl/propargyl silanes, [7][8][9][10][11][12][13][14] carbonyl compounds, 15,16 phenols, 17 α-stannyl nitriles, [18][19][20][21] and enol silyl ethers 22 have been found to be suitable for the rearrangement process. Despite the progresses made, the reaction scope of carbonyl nucleophiles is limited to structurally de ned carbonyl compounds ( Fig.…”