@article{oai:kanazawa-u.repo.nii.ac.jp:00014995,
 author = {Okado, Ryohei and Nowaki, Aya and Matsuo, Jun-ichi and Ishibashi, Hiroyuki},
 issue = {1},
 journal = {Chemical and Pharmaceutical Bulletin},
 month = {Jan},
 note = {A catalytic amount of tin(IV) chloride catalyzed formal [4+2] cycloaddition reaction of di-tert-butyl 2-ethoxycyclobutane-1,1-carboxylate with ketones or aldehydes to give diethyl 6-ethoxydihydro-2H-pyran-3,3(4H)-dicarboxylates, whereas two equivalents of trimethylsilyl triflate promoted tandem [4+2] cycloaddition and lactonization to afford 3-oxo-2,6-dioxabicyclo[2.2.2]octane-4-carboxylate esters.},
 pages = {21--22},
 title = {Formal [4+2] Cycloaddition of di-tert-Butyl 2-Ethoxycyclobutane-1,1-dicarboxylate with Ketones or Aldehydes and Tandem Lactonization},
 volume = {60},
 year = {2012}
}