Table 1.

Allenylboration of R_LR_SCO with 1

RL	RS	1	series	6(%)a	% eeb (abs config)
Ph	Me	S	a	74	91 (S)
Ph	Me	R	a	85	93 (R)
Ph	Et	R	b	65	76 (R)
Et	Me	R	c	71	74 (S)
Bu	Me	S	d	80	81 (R)
i-Pr	Me	R	e	71	84 (R)
t-Bu	Me	S	f	66	83 (S)
TMS	Me	S	g	62	90 (R)
CH2=CH	Me	S	h	64	61 (S)

^aThe a series was performed with both (−)-1R and (+)-1S. The aS, b, f and h series were conducted employing an oxidative work-up. For the remaining examples, the intermediate 5 was isolated and converted to 6 and either 4 or 8 was recovered (69–81%) via the NMPE work-up procedure.

^bProduct ee determined by conversion to the Alexakis esters⁶ and analysis by ³¹P NMR.