Stereoselective Reduction of β-Hydroxy Ketones to 1, 3-Diols with the Aid of a Terphenyboronic Acid
1-Hydroxy-6,8-diphenyl-1,2,3,4-tetrahydro-2-oxa-1-boranaphthalene (terphenylboronic acid <B>1</B>), is employed for stereoselective reduction of acyclic and cyclic <I>β</I>-hydroxy ketones. The terphenylboronic acid <B>1</B> and acyclic <I>β</I>-hydroxy ketones <B>2</B> are converted to the corresponding boronates by azeotropic removal of water. The resulting boronates are treated <I>in situ</I> with reducing reagents to give <I>syn</I> 1,3-diols <B>3</B> almost exclusively. <I>Anti</I> <I>α</I>-substituted <I>β</I>-hydroxy ketones <B>8</B> are also reduced to give <I>anti</I>, <I>anti</I> 1,3-diol <B>9</B> stereoselectively. Furthermore, the reduction of 3-hydroxy-1-cyclopentanone gives a <I>cis</I> diol <B>11</B> in high selectivity.
- Chemistry letters
Chemistry letters 1996(7), 539-540, 1996-07
The Chemical Society of Japan