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 )‐CH 3 El IV (R 2 ) 2 CR 3 C(C 2 H 5 )B(C 2 H 5 ) 2 [R 2,2,3 = CH 3 : 1a ; R 2 = C 2 H 5 , R 2,3 = CH 3 : 1b ; R 2,2 = C 6 H 5 , R 3 = CH 3 : 1c ; R 2,2 = CH 3 , R 3 = C 6 H 5 : 1d ; R 2,2 = CH 3 , R 3 = c‐C 6 H 11 : 1e ] add KOH in THF at – 20°C to form the pure solid 1:1 adducts KOH‐1El IV with El IV = Si, Sn, and Pb. Above ≥0°C compounds KOH‐ 1 Si liberate quantitatively R 2 H to give the potassium salts of the cyclic anions K‐2a to K‐2e . With Me 4 NCl or Me 3 NHCl the corresponding salts Me 4 N‐ 2 or Me 3 NH‐ 2 are obtained from K‐2. Above ≈80°C KOH‐ 1a Ge and KOH‐ 1a Sn eliminate gas (CH 4 , C 2 H 6 ) with formation of mixtures. The compounds KOH‐ 1 El IV and K‐ 2 Si are characterized by multi‐NMR spectroscopy ( 1 H, 11 B, 13 C, 17 O, 29 Si, 119 Sn, 207 Pb), and the NMR data of KOH‐ 1a El IV are compared to the data of the compounds .