Synthesis and characterization of novel intramolecularly base-stabilized BEt2 and BEt derivatives: molecular structures of 1-Et2BOCPh2-2-NMe2C6H4, 1-(CH3COO)EtBOCCy2-2-NMe2C6H4 and BEt(1-OCPh2CH2-2-NMe2C6H4)2

The reaction of BEt3 with the (2-dimethylaminophenyl)alcohols 1-HOX-2-NMe2C6H4 [X = CPh2 (1), CCy2 (2), CPh2CH2 (3)] [1:1 (for 1–3) or 1:2 (for 3)] in the presence of tBuCO2H as catalyst gave the BEt2 or BEt derivatives 1-Et2BOX-2-NMe2C6H4 [X = CPh2 (4), CCy2 (5), CPh2CH2 (7)] and BEt(1-OCPh2CH2-2-NMe2C6H4)2 (8). Treatment of 5 with acetic acid gave 1-(CH3COO)EtBOCCy2-2-NMe2C6H4 (6). Compounds 4–8 were characterized spectroscopically (NMR, IR, MS). Crystal structure determinations were carried out on 4, 6 and 8. For the chiral compound 6, both enantiomers are present in the unit cell.