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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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