110969-19-2Relevant academic research and scientific papers
Copper(I)-Catalyzed Stereo- and Chemoselective Borylative Radical Cyclization of Alkyl Halides Bearing an Alkene Moiety
Iwamoto, Hiroaki,Akiyama, Sota,Hayama, Keiichi,Ito, Hajime
, p. 2614 - 2617 (2017)
The stereoselective borylative radical cyclization of alkyl halides containing an alkene moiety was developed using a copper(I)/diboron catalyst system. The optimized reaction conditions allowed us to control the chemoselectivity between the allylic substitution and the borylative radical cyclization. The borylation products were subsequently converted to highly functionalized organic compounds by derivatization of the newly formed C-B bond. This borylative radical cyclization offers a novel methodology for the stereoselective synthesis of various heterocyclic compounds.
Stereoselective synthesis of heterocyclic zinc reagents via a nickel-catalyzed radical cyclization
Vaupel, Andrea,Knochel, Paul
, p. 5743 - 5753 (2007/10/03)
Unsaturated iodo or bromo acetals of type 2 undergo a smooth cyclization mediated by diethylzinc (2 equiv) and Ni(acac)2 as catalyst (2-5 mol %). These cyclizations proceed via a radical mechanism affording a (tetrahydrofuranylmethyl)zinc halide of type 1, which can be reacted with various electrophiles after a transmetalation with CuCN·2LiCl. High stereoselectivities are usually observed in the ring closures, especially if monocyclic cyclization precursors are used. In these cases, bicyclic products of the endo-configuration are obtained with over 94% diastereoselectivity. The synthetic method has been extended to the preparation of a nitrogen heterocycle and over 98% pure trans-4,5-disubstituted γ-butyrolactones. A short enantioselective synthesis of (-)-methylenolactocine (3) using the radical cyclization and a novel oxidation of α-silyl zinc peroxide as a key step is also described.
General Synthetic Route to γ-Butyrolactones via Stereoselective Radical Cyclization by Organotin Species
Ueno, Yoshio,Moriya, Osamu,Chino, Kunitake,Watanabe, Masaru,Okawara, Makoto
, p. 1351 - 1356 (2007/10/02)
A new method for the preparation of γ-butyrolactones is described in which the key step is the highly stereoselective radical cyclization of bromoacetals to 2-alkoxytetrahydrofurans in the presence of polymeric or low-molecular weight organotin species. 2-Alkoxytetrahydrofurans can be easily converted into γ-butyrolactones by Jones oxidation.
