Beilstein J. Org. Chem.2021,17, 2270–2286, doi:10.3762/bjoc.17.145
complex or active nucleophiles.
In 2014, Jacobsen et al. developed a highly enantioselective selenocyclization reaction of olefins 26, using the chiral squaramide 28 as a dual hydrogen bond donor (Scheme 6) [16]. Although early-stage enantio-enrichment during the introduction of selenium is hard to
) vinylboronic acids.
Enantioselective selenocyclization catalyzed by squaramide 28.
Desymmetrization of meso-aziridines catalyzed by bifunctional thiourea catalyst 31.
Anion-binding-catalyzed desymmetrization of a) meso-aziridines catalyzed by chiral triazolium catalyst 34 by Ooi et al., and b) oxetans
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Graphical Abstract
Figure 1:
a) Binding interactions in the chloride channel of E. coli. and b) examples of chloride, cyanide, n...
Beilstein J. Org. Chem.2015,11, 1865–1875, doi:10.3762/bjoc.11.200
and are consistent with our experimental results. The preferred pathway for formation of 5-exo products is confirmed.
Keywords: density functional theory; fused bicyclic hydantoins; intermediate; reaction mechanism; regioselectivity; selenocyclization; Introduction
Hydantoins, a class of
selenocyclization of 5-alkenylhydantoins leading to fused bicyclic products [24]. To our best knowledge, no previous theoretical work has reported on this reaction. In this paper, density functional theory (DFT) [25][26][27][28] is utilized to understand the mechanism and selectivity of this key step in the
work has provided the first theoretical study of the selenocyclization of 5-alkenylhydantoins. By 1H NMR monitoring of the reaction we proposed a five-step mechanism which involves the intermediate formed by the addition of selenium reagent on starting 5-alkenylhydantoin. The Markovnikov-type product
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Graphical Abstract
Scheme 1:
Proposed mechanism for the selenocyclization of model substrate 1.