1,1-Carboboration Reactions of Strongly Electrophilic 2-Borylethyl Thioethers

• Published in: Zeitschrift für Naturforschung. B, A journal of chemical sciences Vol. 69; no. 11; pp. 1357 - 1364
• Main Authors: Eller, Christina, Billmann, Bastian, Daniliuc, Constantin G., Kehr, Gerald, Erker, Gerhard
• Format: Journal Article
• Language: English
• Published: TUBINGEN Verlag der Zeitschrift für Naturforschung 01.12.2014; Verlag Z Naturforsch
• Subjects: Alkenylboranes; Boron; Chemistry; Chemistry, Inorganic & Nuclear; Chemistry, Organic; Frustrated Lewis Pairs (FLPs); Physical Sciences; Science & Technology; Sulfur; FRUSTRATED LEWIS PAIR; Boron; ACTIVATION; Frustrated Lewis Pairs (FLPs); 1,1-ORGANOBORATION; Sulfur; Alkenylboranes; BOND
• ISSN: 0932-0776; 1865-7117
• DOI: 10.5560/znb.2014-4190

The RSCH CH B(C boranes 3a (R=Ph) and 3b (R=Et) were in situ generated by HB(C hydroboration of the respective vinylthioethers. Their treatment with R -C≡C- SiMe acetylenes resulted in clean 1,1-carboboration to give the respective RSCH CH -substituted alkenylboranes 4 (3 examples). Likewise, the reagents 3 underwent 1,1-carboboration with the acetylenes Ar P-C≡C-SiMe to give the tetrasubstituted alkenylboranes 6, featuring a geminal pair of RSCH CH =B(C substituents at one carbon atom and the Me Si=PAr pair at the other (3 examples). The compounds 6 feature an internal B···P interaction. The conceptually related Mes PCH CH B(C borane (2) does not undergo 1,1-carboboration with ArS-C≡C-SiMe but forms the 1,2-P=B-FLP addition product 7 to the acetylene instead. Compounds 4a, 4c, 6a, and 7 were characterized by X-ray diffraction.