Synthesis and structures of α-lithiated vinyl ethers. Issue 33 (16th August 2018)

• Record Type: Journal Article
• Authors: Ho, Thanh C.; Congmon, Jonathan; Zhou, Zhe; Tius, Marcus A.; Pratt, Lawrence M.
• Is Part Of: Tetrahedron. Volume 74:Issue 33(2018)
• Page Start: 4445
• Page End: 4455
• Publication Date: 2018-08-16
• Subjects: Lithium -- Aggregate -- NMR -- Synthesis -- Computational; Chemistry, Organic -- Periodicals; 547.005
• DOI: 10.1016/j.tet.2018.07.019
• Languages: English
• ISSNs: 0040-4020

Abstract

Abstract: The structures of α-lithiated vinyl ethers were explored on the basis of a combined computational and NMR study. Calculations (M06/6-31 + G(d)) on free energies of aggregate formation for a series of α-lithiated vinyl ethers indicated that the tetramer is generated preferentially in both the gas phase and THF solution, except for cyclohexylidene derivatives. (1-(Methoxymethoxy)vinyl)lithium, (2, 2-difluoro-1-(methoxymethoxy)vinyl)lithium, and (1-butoxyvinyl)lithium were prepared in NMR tubes by the deprotonation of alkyl/alkoxylalkyl vinyl ethers or by the transmetalation of tin compounds. The NMR spectra of these lithium species in THF solution showed that in each species one aggregate is primarily present at 173 K, which is consistent with the preference of the tetramer. Graphical abstract: Image 1