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47.1.1.1.3.4 Method 4: Z-Selective Wittig–Horner Alkenation

DOI: 10.1055/sos-SD-047-00004

Schobert, R.; Hölzel, C.; Barnickel, B.Science of Synthesis, (20104746.

The Horner (also known as WittigHorner) reaction, named after Leopold Horner, employs phosphine oxide anions instead of phosphorus ylides to alkenate aldehydes and ketones.[‌353‌] For that purpose an alkyl-substituted diphenylphosphine oxide 96 is first treated with potassium tert-butoxide or sodium amide and then with the carbonyl compound to give the alkene 97. When a lithium base is used, the corresponding β-hydroxyphosphine oxide 98 may be isolated (Scheme 34). Since the one-step version of the WittigHorner reaction mainly leads to E-alkenes 97, it is covered in Section 47.1.1.1.4.2.

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Meeeeeeeeee 88

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Meeeeeeeeeee Meeeeeeee

8-Meeeee-8-[(8M)-eeee-8-eeee]-8,8-eeeeeeeee [(M)-888, M8=8-(8-Meeeee-8,8-eeeeeeee-8-ee)eeeee; M8=Me]; Meeeeee Meeeeeeee:[‌888‌]

Meeee e M8 eeeeeeeeee, 8.88M MeMe (8.8eM, 88.8eeee) eee eeeee ee e eeee ee eeeeeeeee eeeee 88 [M8=8-(8-eeeeee-8,8-eeeeeeee-8-ee)eeeee; 8.8e, 88.8eeee] ee eeeee MMM (88eM) ee 8°M. Meeee 88eee, eee eeeeee eeee eee eeeeee ee 88°M eee eeeeeee eeee e eeee ee eeeeeeeeeeee (8.8e, 88.8eeee) ee MMM (88eM) eeeeeeeee eeee MeMe. Mee eeeeeeeeeee eeee eee eeeeeee ee eeee ee ee, eee eee. ee MM8Me (88eM) eee eeeee. Mee eeeeeee eeeee eee eeeeeeeee eeee Me8M (8 × 88eM, 8 × 88eM), eee eeeeeeee eeeeeee eeeeee eeee eeeee (Me8MM8), eee eee eeeeeeee eeee eeeeeeeeee eeeee eeeeeee eeeeeeee. Meeeee eeeeeeeeeeeeee (eeeeee eee, MeMMe) eeee eeeeeee-888 ee eeeeeee; eeeee: 8.88e (88%); ee 888888°M (MeMMe); Me 8.88 (MeMMe).

88% MeM ee eee (888ee, 8.88eeee) eee eeeee ee e eeee ee eeeeeee eeeeeee-888 [M8=8-(8-eeeeee-8,8-eeeeeeee-8-ee)eeeee; 8.88e, 8.88eeee] ee MMM (88eM). Mee eeeeeee eee eeeeee ee 88°M eee 8e eee eeee eeeeee eeee e eeeeeee ee Me8M (88eM) eee M8M (88eM). Mee eeeeeee eeeee eee eeeeeeeee eeee Me8M (8 × 88eM), eee eee eeeeeeee eeeeeee eeeeee eeee eeeee (Me8MM8) eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee ee eeee eee eeeeeee ee e eeeeeeeee eeeeee; eeeee: 888ee (88%); ee 8888°M (88Meee).

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