Table 2. Scrambling of Alkyl Fragments upon Alkyllithium Addition and Cross-Coupling.

entry	R–Li	temp (°C)	selectivitya21a/21b
1	nBuLi	23	95–60b/5–40
2	nBuLi	0	65/35
3	nBuLi	45	85/15
4	iPr–Li	23	68/32
5	iPr–Li	0	61/39
6	tBu–Li	23	<1/99c,d
7	tBu–Li	0	<1/99c,d

^aAs determined by GC/MS analysis.

^bSelectivity varied under identical reaction conditions.

^cVarying amounts of homocoupling (bis-benzaldehyde) were also observed.

^dReversed selectivity: only the isobutyl coupled benzaldehyde observed.