Abstract The triborylmethide ions,[(RO) 2 B] 3 C−, from the reaction of methyllithium with the methyl ester of methanetetraboronic acid, C [B (OMe) 2] 4, or the pinacol ester, C (BO 2 C 2 Me 4) 4, condense readily with ketones, R′ 2 CO, to form alkene-1, 1-diboronic esters, R′ 2 C C [B (OR) 2] 2. The reaction is a general one and tolerates other functional groups, including α-chloro, carbethoxy, and tertiary amino substituents. Acetaldehyde and ...
![2-[3-chloro-2-methyl-1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)prop-1-enyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure](https://image.chemsrc.com/caspic/083/52221-74-6.png)
![2-[3-chloro-2-(chloromethyl)-1-(4,4,5,5-tetramethyl-1,3,2-dioxaborolan-2-yl)prop-1-enyl]-4,4,5,5-tetramethyl-1,3,2-dioxaborolane Structure](https://image.chemsrc.com/caspic/383/52221-79-1.png)