{
  "abstract": "Despite the widespread utility of α-halo lithium carbenoids in boron homologations, their solution-state aggregation structures remain unresolved. In this work, a rapid-injection NMR study was undertaken to characterize unstabilized α-halo lithium carbenoids at –105 °C. 13C–6Li scalar coupling established direct carbon–lithium connectivity, and DOSY NMR revealed that the lithium carbenoids exist as monomeric species solvated by THF. Next, the 1,2-metalate rearrangement rates were measured by trapping the α-bromo lithium carbenoid with arylboronic esters and monitoring the conversion of the 8-B-4 complexes generated in situ. The kinetic studies reveal that ring size, backbone substitution, and donor identity strongly influence the rate of the 1,2-metalate rearrangement. Detailed computational studies further confirmed that the lower 1,2-metalate rearrangement barriers of the more reactive boronic esters arise from the combination of the release of steric strain (B-strain), charge redistribution, and more favorable access to the reactive antiperiplanar rotamer of the 8-B-4 complex. Finally, these structure–reactivity relationships were translated into synthetic advances where a faster-migrating 2,4dimethylpentan-2,4-diol boronic ester enabled productive homologation of carbamate-derived carbenoids under mild conditions in which the corresponding BPin boronic ester derivative afforded no detectable homologation product.",
  "abstract_shown": true,
  "affiliations": [
    "Department of Chemistry",
    "Texas A&M University",
    "University of Pennsylvania"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 5,
  "authors": [
    {
      "affs": [
        0,
        1
      ],
      "name": "Seokmin Kang"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Kate V. Grimley"
    },
    {
      "affs": [
        0,
        2
      ],
      "name": "Jin Qian"
    },
    {
      "affs": [
        0,
        2
      ],
      "name": "Andrew F. Zahrt"
    },
    {
      "affs": [
        0,
        1
      ],
      "name": "Andy A. Thomas",
      "orcid": "0000-0001-6336-5566"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/e62jk5vvqzbbv.bib",
  "cited_by": 0,
  "doi": "10.26434/chemrxiv.15010914/v1",
  "fulltext_url": null,
  "id": "e62jk5vvqzbbv",
  "issns": [],
  "landing_url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010914/v1",
  "language": null,
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "openalex",
      "1605|Organoboron and organosilicon chemistry"
    ]
  ],
  "openalex": "W7223338957",
  "pdf_url": null,
  "pmcid": null,
  "pmid": null,
  "published": "2026-10-22",
  "publisher": "American Chemical Society (ACS)",
  "ris": "https://research.draconitic.com/paper/e62jk5vvqzbbv.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T12:17:26Z",
      "native_id": "10.26434/chemrxiv.15010914",
      "source": "chemrxiv",
      "url": "https://chemrxiv.org/doi/full/10.26434/chemrxiv.15010914/v1"
    }
  ],
  "subjects": [
    {
      "field": "chemistry",
      "origin": "openalex:1605|Organoboron and organosilicon chemistry",
      "subfield": "organic"
    }
  ],
  "title": "An RI-NMR and DFT Study of Boron Homologations: Structures of α-Halo Lithium Carbenoids and the Effect of Boronic Ester Structure on 1,2-Metalate Rearrangement Rates",
  "title_text": "An RI-NMR and DFT Study of Boron Homologations: Structures of α-Halo Lithium Carbenoids and the Effect of Boronic Ester Structure on 1,2-Metalate Rearrangement Rates",
  "type": "preprint",
  "updated_at": "2026-10-30T12:17:26Z",
  "url": "https://research.draconitic.com/paper/e62jk5vvqzbbv",
  "venue": "ChemRxiv",
  "versions": []
}