3727-49-9Relevant academic research and scientific papers
Applying the Bent Bond/Antiperiplanar Hypothesis to the Stereoselective Glycosylation of Bicyclic Furanosides
Parent, Jean-Fran?ois,Bertrand, Xavier,Deslongchamps, Ghislain,Deslongchamps, Pierre
, p. 758 - 773 (2020/01/11)
The glycosylation stereoselectivities for a series of bicyclic furanoside models have been carried out in the presence of weak nucleophiles. These results were analyzed through the bent bond/antiperiplanar hypothesis (BBAH) orbital model to test its validity. According to the BBAH, incoming nucleophiles displace one of the two bent bonds of bicyclic oxocarbenium ion intermediates in an antiperiplanar fashion. The glycosylation stereoselectivity is then governed by the displacement of the weaker bent bond as determined by the presence of electron-withdrawing or -donating substituents at C2. Overall, the BBAH analysis expands Woerpel's "inside/outside attack" glycosylation model by considering the stereoelectronic influence of neighboring electron-withdrawing and -donating groups on the nucleophilic addition to oxocarbenium ion intermediates.
Synthesis of α-methylene-γ-lactone structure by cyclization of ω-formylallylsilane in water
Fukushima, Hiroki,Ikegami, Daisuke,Kuroda, Chiaki,Kobayashi, Kenichi
, p. 568 - 574 (2018/05/07)
Surfactant-type protonic acid-promoted intramolecular cyclization of functionalized allylsilanes was studied in water for the synthesis of α-methylene-γ-lactone compounds. ω-Formyl-β-(acetoxymethyl)allylsi-lane afforded carbocyclic compounds in good yields, while the cyclization product was not obtained from the corresponding β-ethoxycarbonyl derivative. It was found that (Z)-β-(acetoxymethyl)allylsilane predominantly afforded the cis-product, while (E)-β-(acetoxymethyl)allylsilane afforded both cis- and trans-products at a ratio of almost 1:1. The stereoselectivity of the cyclization reaction was almost the same as a protonic acid-promoted reaction in CH2Cl2 and was explained by an interaction between the C(Si)–C(alkene) bond and the carbonyl moiety. The cyclization products were converted to α-methylene-γ-lactone compounds.
PREPARATION AND SYNTHETIC APPLICATION OF 2-BROMOALLYLTRIMETHYLSILANE AS A 1-HYDROXYMETHYLVINYL ANION EQUIVALENT
Nishiyama, Hisao,Yokoyama, Hiroshi,Narimatsu, Shinzo,Itoh, Kenji
, p. 1267 - 1270 (2007/10/02)
The 1-trimethylsilylmethylvinyl group, as a 1-hydroxymethylvinyl equivalent, was readily introduced to epoxides with the corresponding Grignard reagent derived from 2-bromoallyltrimethylsilane.Obtained 2-(2-hydroxyethyl)-allylsilanes were converted to α-methylene-γ-lactones via diols.
