Organosubstituierte Kalium‐2,5‐dihydro‐1,2,5‐oxasilaboratolate aus cis‐2‐Boryl‐1‐silylalkenen mit Kaliumhydroxid

Organosubstituted Potassium 2,5‐Dihydro‐1,2,5‐oxasilaboratolates from cis‐2‐Boryl‐1‐silylalkenes with Potassium Hydroxide The compounds (E)‐CH3ElIV(R2)2CR3C(C2H5)B(C2H5)2 [R2,2,3 = CH3: 1a; R2 = C2H5, R2,3 = CH3: 1b; R2,2 = C6H5, R3 = CH3: 1c; R2,2 = CH3, R3 = C6H5: 1d; R2,2 = CH3, R3 = c‐C6H11: 1e] add KOH in THF at – 20°C to form the pure solid 1:1 adducts KOH‐1ElIV with ElIV = Si, Sn, and Pb. Above ≥0°C compounds KOH‐1Si liberate quantitatively R2H to give the potassium salts of the cyclic anions K‐2a to K‐2e. With Me4NCl or Me3NHCl the corresponding salts Me4N‐2 or Me3NH‐2 are obtained from K‐2. Above ≈︁80°C KOH‐1aGe and KOH‐1aSn eliminate gas (CH4, C2H6) with formation of mixtures. The compounds KOH‐1ElIV and K‐2Si are characterized by multi‐NMR spectroscopy (1H, 11B, 13C, 17O, 29Si, 119Sn, 207Pb), and the NMR data of KOH‐1aElIV are compared to the data of the compounds .