Science of Synthesis

Tidwell, T. T., Science of Synthesis, (2006) 23, 575.

Aryl ester enolates can undergo elimination of aryloxy groups to form ketenes that can be captured by other reagents.[‌55‌–‌57‌] The chiral hydroxybinaphthyl ester enolates ‌34‌, generated in situ by asymmetric conjugate addition to the corresponding cinnamate esters ‌33‌, undergo a spontaneous loss of the hydroxybinaphthyloxy group to form the ketenes ‌35‌, which can be trapped by lithium dialkylcuprates to give the chiral ketones ‌36‌ in 73–91% yields (‌Scheme 10‌).[‌56‌] An analogous procedure for a dialkylketene is described in Section ‌23.14.2.1.3.1‌.

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‌Meeeeeeeeee 88‌

Me8	M8	ee (%)	Meeee (%) ee ‌88‌	Mee
Me	Me	88	88	[‌88‌]
8-MeMM8M8	Me	88	88	[‌88‌]
8-MeM8M8	Me	88	88	[‌88‌]
8-MeM8M8	Me	888	88	[‌88‌]
8-eeeeeeee	Me	88	88	[‌88‌]
8-eeeee	Me	888	88	[‌88‌]
8-eeeeeee	Me	888	88	[‌88‌]
Me	Me	88	88	[‌88‌]
8-MeMM8M8	Me	88	88	[‌88‌]
8-MeM8M8	Me	88	88	[‌88‌]
	Me	88	88	[‌88‌]

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(M)-8-Meeeeeeeeeee-8-eee (‌88‌, Me8 = Me; M8 = Me); Meeeeee Meeeeeeee:[‌88‌]

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References