Categories: Synthesis of O-Heterocycles >
Synthesis of 1,3-dioxolanes
A benzotriazole reagent derived from 2-ethoxydioxolane and benzotriazole can be used as a remarkably stable and versatile electrophilic formylating reagent in reactions with Grignard reagents and organozinc reagents. The procedure is mild, efficient, and tolerable to multifunctional organic molecules, which makes it suitable for multistep syntheses.
A. R. Katritzky, H. H. Odens, M. V. Voronkov, J. Org. Chem., 2000, 65, 1886-1888.
A mild and efficient method enables the formation of methylene acetals from 1,2- and 1,3-diols using methoxymethylphenylsulfide, 1,3-dibromo-5,5-dimethylhydantoin (DBDMH), and dibutylhydroxytoluene (BHT). The use of BHT suppresses side reactions and enables high-yielding formation of methylene acetals of various diols, including carbohydrate-type substrates.
T. Maegawa, Y. Koutani, K. Otake, H. Fujioka, J. Org. Chem., 2013, 78, 3384-3390.
The addition of bromomagnesium 2-vinyloxy ethoxide to various aldehydes in the presence of 10 mol% Sc(OTf)3 provides a broad range of functionalized protected aldol compounds. A Swern oxidation-CBS reduction sequence enables the preparation of chiral protected aldol products.
P. Quinio, L. Kohout, D. S. Roman, J. Gaar, K. Karahiosoff, P. Knochel, Synlett, 2016, 27, 1715-1719.
A chiral binaphthyldiimine-Ni(II) complex catalyzes an asymmetric 1,3-dipolar cycloaddition reactions between acyclic carbonyl ylides generated from donor-acceptor oxiranes and both aromatic and aliphatic aldehydes to provide cis-1,3-dioxolanes with high diastereo- and enantioselectivities.
Y. Toda, K. Sato, K. Sato, K. Nagasaki, H. Nakajima, A. Kikuchi, K. Sukegawa, H. Suga, Org. Lett., 2022, 24, 4739-4744.
A thiol-promoted site-specific addition of 1,3-dioxolane to imines through a radical chain process enables a metal-free and redox-neutral conversion of inexpensive materials to a broad range of protected α-amino aldehydes in very good yields using only a catalytic amount of radical precursor. Both the thiol and a small amount of oxygen from air are indispensable to the success of this reaction.
H. Zeng, S. Yang, H. Li, D. Lu, Y. Gong, J.-T. Zhu, J. Org. Chem., 2018, 83, 5256-5266.