Preparation of 2-Silicon-Substituted 1,3-Dienes and Their Diels−Alder/Cross-Coupling Reactions

Abstract

2-Triethoxysilyl-substituted 1,3-butadiene has been prepared in 30-g quantities from chloroprene via a simple synthetic procedure. Silatrane- and catechol-substituted analogues of this main group element substituted diene were then prepared on a 10-g scale by ligand exchange and characterized by X-ray crystallography in addition to standard spectroscopic techniques. 2-Dimethylphenylsilyl-1,3-butadiene has also been prepared from chloroprene on an 8-g scale. Diels-Alder reactions of these dienes are reported as well as subsequent TBAF-assisted/Pd-catalyzed Hiyama cross-coupling reactions of those Diels-Alder adducts. Silicon-substituted cycloadducts and cross-coupled products were also characterized by NMR spectroscopy and, in two cases, by X-ray crystallography.

Efficient Access to the Functionalized Bicyclic Pharmacophore of Spirolide C by Using a Selective Diels–Alder Reaction

“…First, the substrates were treated with the Cu catalyst in CH 2 Cl 2 at 25 °C and then heated at reflux for two days; however, the reaction unexpectedly did not proceed at all (Table , entry 3). Although a simple 2‐silatrane diene has been reported to be almost twice as reactive as Danishefsky′s diene, 2‐silatrane diene 6 seemed to be less reactive than 2‐silyloxy diene 5 , presumably owing to the increased steric repulsion between the large 2‐silatrane moiety and the 3‐methyl group, which potentially hampered the s‐ cis conformation that would be favorable for the reaction. To improve the considerably decreased reactivity, the solvent was changed to toluene and the reaction mixture was stirred at 80 °C for six days, which led to a slight formation of the cycloadducts (12 % yield) as an isomeric mixture (stereostructure not determined; Table , entry 4).…”

Silatranes: a review on their synthesis, structure, reactivity and applications

“…A characteristic shielding of 29 Si and deshielding of 15 N was observed with the increase in electron withdrawing effect of heterocyclic substituent. Some more silatranes such as 1-(N-heterylmethyl)silatranes with benzimidazole (60), imidazole (61), indole (62), 3,5-dimethylpyrazole (63), and phthalimide (64) moieties can be obtained from similar reaction pathways. [51][52][53] Additionally, this method was also used to synthesize 4-methyl-1-phenyl-2-(silatranylmethyl)-3-pyrazolidone (65).…”

Ultrasonic synthesis and crystal structure analysis of two trimethylsilyloxy-substituted bicyclo[2.2.2]octene derivatives

“…Due to steric-hindrance in the ring both the substituents adopt endo-conformation, this is in good agreement with the theoretical predictions. 20,21 The phenyl ring of N -benzylmaleimide group is positioned axially to the methyl-pyrrolidine-2,5-dione ring with a dihedral angle of 67.36 (5) • . In the molecule, cyclohexene rings A(C6/C7/C8/C9/C10/C11) and B(C6/C7/C8/C9/ C1/C2), and the cyclohexane ring C(C6/C1/C2/C9/ C10/C11) of the bicyclo[2. and −176.25 (1) • , respectively for ring C. 19 Both the oxygen atoms of the pyrrolidine-2,5-dione ring are taking part in the hydrogen bond.…”