Table 2.

Optimization of reaction conditions for exclusive syn-β-OH elimination

Entry	[Rh]	T (oC)	t (h)	Yield, eea of (S)-3aa (%)	Recovery of (S)-1a (%)	Yield of byproducts (%)
1	[Cp*RhCl2]2	rt	5	17, 99	79	5
2b	[Cp*RhCl2]2	rt	5	7, 99	86	8
3	[Cp*RhCl2]2	50	7	27, 99	71	2
4	[Cp*RhCl2]2	70	7	35, 99	63	2
5	[Cp*RhCl2]2	90	7	45, 98	51	3
6	[Cp*RhCl2]2	90	19	40, 98	42	/
7c	Cp*Rh(MeCN)3(SbF6)2	50	16	/, /	/	8
8c,d	Cp*Rh(OAc)2	50	4.5	90, 99	/	7

Reaction conditions: (S)-1a (0.2 mmol), PhB(OH)₂ (0.4 mmol), and [Rh] (5 mol%) in 1,4-dioxane (1 mL) at T ^oC unless otherwise noted. Yield and recovery were determined by ¹H NMR analysis using dibromomethane as the internal standard.

^aDetermined by HPLC analysis.

^b2.0 Equiv of NaOAc were used.

^cThe reaction was conducted in the absence of NaOAc.

^d3.0 Equiv of 2a were used.