Theoretical study on the consecutive 1,2-hydroboration and 1,1-organoboration reactions of alkyn-1-yl(vinyl)silane with borane

Activation of Silicon- and Tin-Carbon Bonds. 1,1-Carboboration of Alkynylsilanes and -stannanes

“…The hydroborating reagent 9borabicyclo[3.3.1]nonane, 9-BBN, (Lane and Brown, 1971;Brown et al, 1974, Köster andGriaznov, 1961) reacts selectively with the vinyl group, placing the boryl unit at the terminal carbon atom (Brown, 1975). The stereochemistry is favourable for intra-molecular Si-C bond activation, and 1,1-carboboration leads to the 1-silacyclopent-2-ene derivative (Wrackmeyer et al, 2014b) in agreement with theoretical calculations (Xia et al, 2008).…”

Recent Advances in Boron‐Substituted 1,3‐Dienes Chemistry: Synthesis and Application

“…The main product is the (Z)i somer. [22][23][24] The reaction is initiated by ac leavage of the polar metalÀcarbonb ond by the electron-deficient boron atom to form an alkynylboratelike zwitterionic intermediate, followedb yt he 1,2-shift of one organyl group from boron to the neighboring alkynyl carbon atom,l eadingt ot he organometallic-substituted alkene product substituted with an element from roup 14 of periodic table as wella ss ome other metals such as Ti andP t. [25][26][27][28][29] Early prog-ress was made by the conversion of BR 3 into trialkyl(alkynyl)borates [R 3 BÀCCÀCÀR 2 ] À ,f ollowed by their reactionw ith electrophilesa nd salt elimination57.T he application of alkenylmetalloidso rd ialkynylmetalloids in carboboration process is also an effective method for obtainingb oronate-substituted 1,3dienes 58 (Scheme 17).…”

Hydroboration of vinylsilanes providing diversity-oriented hydrophobic building blocks for biofunctional molecules

“…The calculation conditions were set following the report of Xia and coworkers. 17 The Markovnikov-type transition state (2 ‡ ) was increasingly favored over the anti-Markovnikov transition state (3 ‡ ) with increase in the numbers of the phenyl groups (Me 3 < Me 2 Ph < MePh 2 < Ph 3 ) (Table . 2). Thus, the results of the DFT calculations were in agreement with the observed regioisomeric ratios of the products.…”