TABLE 1.

Hydroboration/Protodeboronation of Alkynyl Pinacolboronates Bearing Various Functional Groups Pinacolboronates Bearing Various Functional Groups^a

entry	R	product	% isolated yield
1			86
2			84
3			83
4			78
5			77
6			77
7			71
8			66b
9			57c
10			93d
11			-e
12			-e
13			-e

^aAll reactions were carried out on 2 mmol scale in Et₂O (4 mL) using 1:1 starting material/ borane. AcOH (2.2 equiv) was added at 0 °C, then ethanolamine at 0 °C and warmed to rt.

^bThe product was isolated as a 90:10 mixture of cisltrans isomers.

^cThe alkynyl pinacolboronate was not stable, necessitating that it be carried through without characterization.

^dThe product was isolated with 10% of protodeboronation byproducts, which were inseparable by chromatrography or distillation.

^eDecomposition