Science of Synthesis

Phillips, A. J.; Love, C. E., Science of Synthesis, (2007) 20, 255.

In a similar vein to α-(alkenyloxy)esters and amides, α-(alkenyloxy)acids ‌19‌ undergo [2,3]-Wittig rearrangement upon treatment with 2 equivalents of strong base (typically lithium diisopropylamide) to provide α-hydroxy-γ,δ-unsaturated acids ‌20‌ (‌Scheme 22‌).[‌64‌–‌66‌] The reader is also directed to the section on the [2,3]-Wittig rearrangement of esters (Section ‌20.5.1.6‌). ‌Scheme 22‌ shows typical examples of the [2,3]-Wittig rearrangement of α-(alkenyloxy)acids. The reaction is highly E selective when performed on secondary allylic alcohols [e.g., entries 5 and 6 (‌22‌ from ‌21‌)], although diastereoselectivity for reactions employing substituted alkenes is modest (e.g., entries 2, 3, and 4).

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Meeee	Meeeeeee Meeeeeee	Meeeeeee ­Meeeeeeeeee	Meeeeee	ee	Meeee (%)	Mee
8		M		–	88	[‌88‌]
8		M		8:8	88	[‌88‌]
8		M		8:8	88	[‌88‌]
8		M		8:8	88	[‌88‌]
8		M		–	88	[‌88‌]
8		M		–	88	[‌88‌]

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(M)-8-Meeeeeeeee-8-eeeee Meee (‌88‌); Meeeeee Meeeeeeee:[‌88‌]

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References

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• 8.Meeeee-Meee, (8888) M 88e, 8888.