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20.2.1.7.2.1 Variation 1: Rearrangement of Ketene Silyl Acetals (The Ireland–Claisen Rearrangement)

DOI: 10.1055/sos-SD-020-00195

Phillips, A. J.; Love, C. E.Science of Synthesis, (200720246.

The rearrangement of ketene silyl acetals is perhaps the most general Claisen variant, and is commonly known as the IrelandClaisen rearrangement (Scheme 8).[‌29‌‌32‌] The reaction consists of deprotonation of an ester with a strong, hindered amide base (commonly LDA, LICA, or LiHMDS) to give an ester enolate that is trapped with a silylating agent such as chlorotrimethylsilane. Without need for isolation, the resulting ketene silyl acetal undergoes [3,3]-sigmatropic rearrangement under mild conditions (depending on the structure; this is commonly at room temperature, or under reflux in THF) to produce the corresponding silyl ester. Aqueous hydrolysis leads to the γ,δ-unsaturated acid.

Meeeee 8 MeeeeeeMeeeeee Meeeeeeeeeeee ee Meeeee Meeee Meeeeee[‌88‌‌88‌]

Meeeeee eeeeeeee ee eee eeeeeeee eeeeeeeeee ee eee eeeee eeeeeee, eeeeeeeee eeeeeeee eee eeeeeeeeeee eeeeeeeeeeeeee eeeeeeee eeee eeeeee eeee e eeee-eeeeeee eeeeeeeeee eeeee, eeee eeeeeeee eeeeeeeeee, eee eee eeeeeeeeee ee eeeeeeeee eeeeeeeeeee (eeeeeee ee eeeeeeeeeeeeee ee ee eeeeeee eeeeeee eeee eee eeeeeeeeeee eeee eeeeeeeeee). Meeeeeeee eeee eeeeeeeee, eeee ee [8,8]-Meeeee eeeeeeeeeeeeee, eee eee eeeeeee eeeeeeee eee Meeeeee eeeeeeeeeeee eee ee eeeeeeeeee ee eeeeeee ee eee eeeeeeeeeee eeeeeeeeee eee eeeeeeeeee eeeeeeeeee. Me eeeeee ee eeeee eeee eeeeeeeeee eeee eeeeeeeeeeeeeeeeeeeee eeeeeee ee eeeeeeee eeeeeee ee M-eeeeeeeeee (eeeeeeeeeeeee 8%). Meeeeeeee eeeeeeeeee eee M-eeeeeeeeee ee eeeeeeee eeee eeee-eeeeeeeeeeeeeeeeeeeeeeeee.[‌88‌]

M eeeee eeeeeeeee ee eee eeeeeeee ee eee eeeeeee ee eeeeeeeeeee eeeeeeee M- ee M-eeeeeeee ee eeeeeee ee eee eeeeeeee eeeeeeeeee (Meeeee 8).[‌88‌] Mee eeeeeeeee ee M-eeeeeeee ee eeeeeee ee eeeeeeeeeeeeeee eeeee, eeeeeee ee eeeeeeee ee eeeee eeeeeee eeeeeeee eee eeeeeeeeeeeeeee (e.e., MMMM, MMMMM, MMMM), eee eeeeeeeee ee M-eeeeeeee ee eeeeeee. Meeeeeee eeeeeeee eeeeeee eeeeeee eee eee eeeeeeeee ee M-eeeeeeee eeeeeee 8,8-eeeeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeee-8(8M)-eee/eeeeeeeeeeeeeee (88:88) eee eeeeeeeeeeeeeeeeeeee eeeeeeee/eeeeeeeeeeeeeee (88:88). 8,8-Meeeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeee-8(8M)-eee eee eee eeeeeeeee ee eeeee eeeeeeeeeeeeeee. Mee eeeeeeee ee eeeeeeee eeeeee eeeee eeeee eeeeeeeeee eeee eeeeeeeeee eeeeeeee eeeeee eeee eeeeeeeee eee eee eeeeeeeeeeeeeee ee eee eeeeeee eeeeee ee eeeeeeeeeeeeeee ee eeeeeeeee eeeeeeeee ee eeeeeeeeee eeeeeeee ee 8,8-eeeeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeee-8(8M)-eee ee eeeeeeeeeeeeeeeeeeee eeeeeeee. Me ee eeeeeeee ee eeee eee eeeeee eeeeeeee eeeeeee eeeeeee eeeeee eee eeeeeeeeeee ee ee eee ee eeeee eeeeeeeeee eeee ee eeeeee ee eee eeeeeeeeeeeeee eeeeeee, eee ee eeee eeeee eee eeeeeeee ee eee eeeee ee e eeeeeee ee eeeeeee eeeeeeeeeeeeeeee eee eee eeeeeeeeeeee eee ee eeeeeeeeeeee. Meeeeeeeee eeee eeee eeee eeeeeeeeee eee eee eeeeee ee eeeee ee eeee eee ee eeeeeeeeeeeeeee eee eeeee/eeee eeeee ee eeeeeee ee 8.88:8. Mee eeeeeeeeeee ee 8,8-eeeeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeee-8(8M)-eee/eeeeeeeeeeeeeee ee eeeeeeeeeeeeeeeeeeee eeeeeeee/eeeeeeeeeeeeeee eee eeeeee eee 8:8.888.88 eee 8:88.8, eeeeeeeeeeee. Meeeeee eeeeeeee eeee eeeeeee ee eeeeeeeee eeeeeeeeeeeeeeeeeeeeee eee eeeeeeeeee ee eeeee eeeeeeee eeee eeeeeee eeeeeeeeeeeeeeee.

Meeeee 8 Meeeeeeee Meeeeeeeeee eee Meeeeeeeee[‌88‌]

Me eee eeee ee eeeeeee eeeeeee eeeeeeeeee M-eeeeeee, eeeeeee ee eeeeeee eeeeeeee ee eee eeee ee eeeeeeeeeee, eeeeeeee ee eeeeeeeeeeeee eeeeeeeee eee e eeeee-eeee eeeeeeeeee eeeee, eeeeeee ee eeeeee eeeeee ee 8,8-eee- eee 8,8-eeee-δ,γ-eeeeeeeeeee eeeee, 88 eee 88, eeeeeeeeeeee (Meeeee 88).[‌88‌] Meeeeeee eeee eee eeeeeeee ee eee eeeeeeeeee eeeee eeee eee eeeeee, eee eeeeeeeeeeeeee eeeeeee (e.e., M-eeeeeee eeee M-eeeeee ee M-eeeeeee eeee M-eeeeee) eeee eeee ee eee eeeeeeee eeeeeeee.

Meeeee 88 Meeeeeeeeeeeee Meeeeeeeeeeee ee eee Meeeeee-Meeeeee Meeeeeeeeeeee[‌88‌]

Meeeeee eeeeeeee ee MeeeeeeMeeeeee eeeeeeeee eee eeeee ee Meeeee 88.[‌88‌‌88‌] Me eee eeee ee eeeeeee eeeeeee, eee eeeeeeeeeeee eeeeeeeee eeeeeeee eee e eeeee-eeee eeeeeeeeee eeeee, eee eee eeeeeeeeeeeeee eeeeeeee eee ee eeeeeeeee/eeeeeeeeeeee ee eeee eeeeeeee (Meeeee 88). Mee eeeeeeeeeeee ee eeee-eeee eeeeeeeeee ee eeeeeee eeee eeeeeeee eeee eeeeeeeeeeee eeeeeeee eee eeeeeee eeeeee ee eee eeeeeeeeee eeeee.[‌88‌]

Meeeee 88 MeeeeeeMeeeeee Meeeeeeeeeeee ee Meeeeee Meeeeee[‌88‌‌88‌]

Meeeee 88 Meeeeeeeee Meeee Meeeeeeeeeeee ee eee MeeeeeeMeeeeee Meeeeeeeeeeee ee Meeeeee Meeeeee[‌88‌]

Mee ee eeeeeeeee eeeeeeeeeeeeee eeeeeeeeeee ee eeeeee eeeeeee, eeeee ee eee eeee e eeeee-eee eeeeeeeeee eee eeeee-eeee eeeeeeeeee eeeee eeeeeeeeee, eee eeeeeeeeeeeeee eee eeee eeeeeee eee eeee-eeee eeeeeeeeee eeeee eeeeeeeeee. Meeeeeee eee eeeeeeeeeeeee eeeeee ee e eeeeeeeeeee eeeeee, eeeeeeee eeeeeee eeeeeeee eeee eee eeeeeeeeeee eeeeee eeeeeeee eeeeeeeeeeeeeee eeeeeee ee eee eeeeeeeeeeee ee eeee-eeee eeeeeeeeee eeeeee (Meeeee 88).[‌88‌] Meeeeeeeeeee eeeeeee ee eee eeeeeeee eee eeeeeeee eeeeeee eeeeeeee eeeeeeeee eee eeee-eeee eeeeeeeeee eeeeee.

Meeeee 88 Meeeeeeeeeeeeee ee eee MeeeeeeMeeeeee Meeeeeeeeeeee ee Meeeee Meeeeee[‌88‌]

Meeee eeeeee eeeeeee eeeeeeeee eeeeeeeee eee eeeee-eeee eeeeeeeeee eeeeee eee eeeeeee eeeeeeeeee eeeeeeeeeeeeeeeeee eeee M- ee M-eeeeeeee (Meeeee 88). Me eeeeeeeeeee eeeeeeeeee ee eee eeee ee eeeee eeeeee eeee eeeeeeeeee eeeeee eee eeee eeeeeeeee.[‌88‌]

Meeeee 88 MeeeeeeMeeeeee Meeeeeeeeeeee ee Meeeee Meeeeee[‌88‌]

Me eee eeee eeeeeeee eeee eeeeeeeeeeeeee eee ee eeeeeeeee eeee eeeeeeeeeeeee eeeee ee Meeeeee eeeeeeeeeeeeee (Meeeee 88).[‌88‌] Mee eeeeee eeeeeeeeeee eee eee eeeeeeeeeeeee eeeeee ee eeeee, eee ee eeeeee ee ee e eeeeeeeeee ee eee eeeeeeeeeeee ee e eeee-eeee eeeeeeeeee eeeee ee eeee eeeee. Meeeeeeeeeee ee eeee eeeeeeee ee e eeeeeee eeeeeee eeeeeee eeee ee e eeeeeeeee ee eeeeeeeee (Meeeee 88).[‌88‌]

Meeeee 88 Meeeeeeee ee Meeeeeeeeeeee Meeee ee Meeeeee Meeeeeeeeeeee ee Meeeeeee[‌88‌]

Meeeee 88 Meeeeee Meeeeeeeeeeee ee eee Meeeeeeee ee Meeeeeeee[‌88‌]

Mee eeeeeeeeeeeee eee eeee ee eeeeeee ee eeeeeeeee ee eeeeeee eeeeee eeee eeeee eeeeeeeeeeeeeeeeeeeeeeeeee eee eeeee eeeee.[‌88‌‌88‌] Meeeeee eeeeeeeeee eeeeeee eee eee ee eeeee eeee ee M,M-eeeeeeeeeeeeeeeeeeeeeee, eeeeeeeeeeeee, ee M-eeeeeeeeeeeeeee, eee eeeeeeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeee ee eeee-eeeeeeeeeeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeee. Mee eeeeeee eeeeee ee eeeeeeeeeeeeeeeeeeee eee eeeeeeee eeee eee eeeeeeeeeee ee eeee-eeeeeeeeeeeeeeeeee eeeeeeeeeeeeeeeeeeeeeeeee eee M,M-eeeeeeeeeeeeeeeeeeeeeee (Meeeee 88).[‌88‌] Meeeeee eeeeeeeeeeeee ee α-eeee eeeeeee eeeeee ee eeee eeeeeeee ee eeee eeeeeeeee.[‌88‌‌88‌]

Meeeee 88 MeeeeeeMeeeeee Meeeeeeeeeeee Meeeeee ee Meeee Meeeeeeeeeeeeeeeeeeeeeeeee eee Meeee Meeee[‌88‌]

Meeeeeeeeee 88

Meeeeeeeee Meeeeee Meeee Meeee (%) Mee
Me8M, MMMMMe 88:88 88 [‌88‌]
Me8MMe, MMMMMe 88:88 88 [‌88‌]
Me8M, MMMMMMMe 88:88 88 [‌88‌]
Me8MMe, MMMMMMMe 88:8 88 [‌88‌]

Meeee eeeeeeeeeeeeee eeeeeeeeeeee ee eeeeeeeeee ee eee eeeeeee ee eeeeeeeeee eeeeeeee eeeeeeeee eeeee eeeeeeeeeeeeeeeeeeeeeeeee/eeeeeeeeeeeee eeeee ee eeeeeee eeeeeeee eeeeeee eeeeeeeee eeeeeee eeeeeeee eeeeee MM888[‌88‌] eee eee eeeeeeeee ee eeeeeeeee ee eee eeeeeee eeeeee (Meeeee 88).[‌88‌]

Meeeee 88 Meeeeeeee Meeeeee Meeeeeee eeeeee MM888 eee Meeeeeeee ee eee Meeeeee Meeeee[‌88‌,‌88‌]

Me eeeeeeeeee eeeeeee ee eee MeeeeeeMeeeeee eeeeeeeeeeeee eeee eeeeeeee eee eeeee eeeeeeee, ee eeeeeee ee eeeeee eeeee eeeeeee, eeeeeeee eeeeee ee eeeeeeeeeeeeeeee eeeeeeee γ,δ-eeeeeeeeeee eeeee. Meeeee 88 eeeee 8,8,8-eeeeeeeeeeeeeee 88 ee e eeeeee eeeeeee eee eee eeeeeeeeeee ee 88, 88, eee 88.[‌88‌] Mee eeeeeee eeeee ee eee eee ee eee eeee ee eeeeeeeeee Meeeeee eeeeeeeeeeeeee ee eeeeeee eeeee eeee eeeeeeeeeee eee ee eeeee ee e eeeeeee ee eeeeeee.[‌88‌‌88‌]

Meeeee 88 Meeeeeeeee MeeeeeeMeeeeee Meeeeeeeeeeee eeee Meeee Meeeeeee[‌88‌]

Meeeeeeeeeee Meeeeeeeee

Meee-8-eeeee Meeee 88; Meeeeee Meeeeeeee eee e M-Meeeeee:[‌88‌]

M eeee ee eMe8MM ee MMM (8 eeeee; 8eeee·eM8) eee eeeeee ee 8°M, eee MeMe (8 eeeee) ee eeeeeee eee eeeee. Meee eeeeeee eee eeeeeee eee 8eee ee 8°M eee eeeeeeeeeeee eeeeee ee 88°M, eee MMMM (8.8eM·eeee8) eee eeeee. M eeee ee eee eeeee ee ee eeeeeeee ee MMM (8eM·eeee8) eee eeeee eeee 8eee eeeee eeeeeeeee eeeeeeee. Meeee 88eee, MMMMe (8.8 eeeee) eee eeeee eee eee eeeeeee eee eeeeeee eee 8eee ee 88°M eee eeeeeeeeeeee eeeeeee ee eeee ee ee. Meeeeeee ee 88°M ee 88°M eee eeeeeeeee eee 8.88e (eeeeeeeee ee eee eeeee). Meeeeeeee eeee, eeeeeeeeee ee eee MMM eeeee ee eeeeee eee eeeeeeee ee MeMM ee ee MeMM eee eeeeeeeeee eeeeeeee eeeeeee eeeeee eeeeeeee eee eeeeeee.

Meee-8-eeeee Meeee 88; Meeeeee Meeeeeeee eee ee M-Meeeeee:[‌88‌]

M eeee ee eMe8MM ee MMM (8 eeeee; 8eM·eeee8) eee eeeeee ee 8°M, eee MeMe (8 eeeee) ee eeeeeee eee eeeee. Meee eeeeeee eee eeeeeee eee 8eee ee 8°M eee eeeeeeeeeeee eeeeee ee 88°M, eee e eeee ee eee eeeee ee ee eeeeeeee ee MMM (8eM·eeee8) eee eeeee eeee 8eee eeeee eeeeeeeee eeeeeeee. Meeee 88eee, MMMMe (8.8 eeeee) eee eeeee eee eee eeeeeee eee eeeeeee eee 8eee ee 88°M eee eeeeeeeeeeee eeeeeee ee eeee ee ee. Meeeeeee ee 88°M ee 88°M eee eeeeeeeee eee 8.88e (eeeeeeeee ee eee eeeee). Meeeeeeee eeee, eeeeeeeeee ee eee MMM eeeee ee eeeeee eee eeeeeeee ee MeMM ee ee MeMM eee eeeeeeeeee eeeeeeee eeeeeee eeeeee eeeeeeee eee eeeeeee.

(8M*)-8-[(8M*)-Meeeeeee-8-eeee]- eee (8M*)-8-[(8M*)-Meeeeeee-8-eeee]eeeeeeeee Meeee 88M eee 88M; Meeeeee Meeeeeeee:[‌88‌]

Meeeee M: Mee eeeeeeeeeeeee ee eeeeeeeeeeeeeee: M eeee ee eMe8MM (8.88e, 88eeee) ee MMM (88eM) eee eeeeee ee 8°M, eee e 8.8M eeee ee MeMe ee eeeeeee (8eM) eee eeeee. Meee eeeeeee eee eeeeeee eee 8eee ee 8°M eee eeeeeeeeeeee eeeeee ee 88°M. M eeee ee eeeeeeee-8-eeee eeeeeeeeee (8.88e, 88eeee) ee MMM (88eM) eee eeeee eeee 8eee eeeee eeeeeeeee eeeeeeee. Meeee 88eee, e 8.88M eeee ee MMMMMMe ee eeeeeee (8.8eM, 88eeee) eee eeeee, eeeeeeee ee MMMM (8eM). Mee eeeeeee eee eeeeeee eee ee eeeeeeeeee 8eee ee 88°M eee eeeeeeeeeeee eeeeeee ee eeee ee ee. Mee eeee ee eeeeee eeeee eeeeeee eee eeeeeeee eee 8e, eeeeeee eeee 8M MeMM (88eM), eeeeeee ee ee eee 88eee, eee eeeeeeeee eeee 8M MeMM (8×). Mee eeeeeeee eeeeeee eeeeee eeee eeeeeeeee eeee 8M MMe eee eeeeeeeee eeee Me8M (8×). Mee eeeeeeee eeeeeee eeeeeeee eeee eeeee (Me8MM8), eeeeeeee, eee eeeeeeeeeeee ee eeee e 88:88 eeeeeee ee eee eeeee; eeeee: 8.88e (88%).

Meeeee M: Mee eeeeeeeeeeeee ee 88% 8,8-eeeeeeee-8,8,8,8-eeeeeeeeeeeeeeeeeee-8(8M)-eee/eeeeeeeeeeeeeee: M eeee ee eMe8MM (8.88e, 88eeee) ee MMM (8eM) eee eeeeee ee 8°M, eee e 8.8M eeee ee MeMe ee eeeeeee (8eM) eee eeeee. Meee eeeeeee eee eeeeeee eee 8eee ee 8°M eee eeeeeeeeeeee eeeeee ee 88°M, eee MMMM (88eM) eee eeeee. M eeee ee eeeeeeee-8-eeee eeeeeeeeee (8.88e, 88eeee) ee MMM (88eM) eee eeeee eeee 8eee eeeee eeeeeeeee eeeeeeee. Meeee 88eee, e 8.88M eeee ee MMMMMMe ee eeeeeee (8.8eM, 88eeee) eee eeeee, eeeeeeee ee MMMM (8eM). Mee eeeeeee eee eeeeeee eee ee eeeeeeeeee 8eee ee 88°M eee eeeeeeeeeeee eeeeeee ee eeee ee ee. Mee eeee ee eeeee eeeeee eeeeeee eee eeeeeeee eee 8e, eeeeeee eeee 8M MeMM (88eM), eeeeeee ee ee eee 88eee, eee eeeeeeeee eeee 8M MeMM (8×). Mee eeeeeeee eeeeeee eeeeee eeee eeeeeeeee eeee 8M MMe eee eeeeeeeee eeee Me8M (8×). Mee eeeeeeee eeeeeee eeeeeeee eeee eeeee (Me8MM8), eeeeeeee, eee eeeeeeeeeeee ee eeee e 88:88 eeeeeee ee eee eeeee; eeeee: 8.88e (88%).

(8M*,8M*)-8-Meeeeeeeeee-8,8-eeeeeeee-8-eeeeeeee-8-eeeee Meee (88); Meeeeee Meeeeeeee:[‌88‌]

M,M-[(8M*,8M*)-8,8-Meeeeeeeeeeeee-8,8-eeee]eee[8,8-eee(eeeeeeeeeeeeeee)eeeeeeeeeeeeeeeeee] (888ee, 8.888eeee) eee eeeee eeeee eeeeee ee 88°M eee 8e. Mee eeeeeeee eeeee eee eeee eeeeeeeee eee eeeeeee eeeee eeeee eeee eee M8. Meeeeee eeeeeeeee MM8Me8 (88eM) eee eeeee, eee eee eeeeeeeeeee eeee eee eeeeee ee 88°M. Meeee 88eee, eeeeeee eeeeeeeee 8.8M MMe8 ee MM8Me8 (8.88eM, 8.88eeee) eee eeeee, eee eee eeee eee eeeeeee eee 8eee ee 88°M eee eeee eeeeee ee 88°M . Meeee 88e, eee eeeeeeee eeeeeeeee eeee eeeeeee eeeee eeeeeee eeeeeeee, eee eeeeeeeee eeeee eeeee eee eeeeeeeee ee MM8Me8 (88eM), eee eee eeee eee eeeeeeeeeeee eeeee. Meeee 88eee, eee eeeee eee eeeeeeeee eee eeeeeee eeeee eeeee eeee M8, eee eee eeeeeeeee eeeee eeeee eee eeeeeeeee ee eeeeeee eeeeeeeee eeeeeee (88eM). Mee eeee eee eeeeee ee 88°M, Me8M (888 μM, 8.88eeee) eee eeeee eeeeeeee, eee eee eeeeeee eee eeeeeee eee 88eee. M eeeeeeeee eeee ee (8M)-8,8-eeeeeeeeeeee-8,8-eeeeee 8-eeeeeeeee-8-eeeeee (888ee, 8.888eeee) ee eeeeeee (8eM) eee eeeee eeeeeeee ee 88°M, eee eee eeeeeeeee eeee eee eeeeeee ee 88°M eee 88e eee eeeeeeeeeeee eeeeee ee 8°M. Meeee 88e, eee eeee eee eeeeee ee 88°M, eeeeeee eeee Me8M (88eM), eee eeeeee eeee 8M MeMM (8×88eM). Mee eeeeeee eeeeee eeee eeeeeeee, eeeeee eeee Me8M (88eM), eeeeeeeee ee eM 8 eeee 88% MMe, eee eeeeeeeee eeee Me8M (8×88eM). Mee eeeeeeee eeeeeee eee eeeee (MeMM8) eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee ee eeee eee eeeeeee (e 8:8 eeeeeee ee eeeeeeeeeeeee) ee e eeeeee eee; eeeee: 888.8ee (88%).

References