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47.1.1.4.4.1 Variation 1: Methylenation with the Nysted Reagent

DOI: 10.1055/sos-SD-047-00100

Petasis, N. A.Science of Synthesis, (201047207.

The Nysted reagent 111[‌143‌] is commercially available and has been used for the methylenation of aldehydes and ketones in the presence of titanium(IV) chloride or boron trifluoridediethyl ether complex (Table 16).[‌149‌,‌167‌,‌168‌‌170‌] Furthermore, it works well in many cases where the Wittig reaction results in lower yields or product decomposition. Methylenation in the presence of catalytic amounts of boron trifluoridediethyl ether complex proceeds in good yields with aromatic aldehydes (Table 16, entries 1 and 2),[‌149‌,‌167‌] alipathic aldehydes (entry 3),[‌149‌] and unsaturated aldehydes (entry 4).[‌149‌] Chiral aldehydes, such as (S)-2-phenylpropanal, are observed to undergo methylenation without any epimerization (entry 3). It is also possible to methylenate aldehydes in the presence of ketones (entry 5).[‌149‌] The use of a low-valent titanium(II) chloride additive in addition to the boron trifluoridediethyl ether complex catalyst enables the methylenation of ketones, which takes place without any epimerization (entry 6).[‌149‌] The use of titanium(IV) chloride together with the Nysted reagent is also effective for the methylenation of aldehydes and acyclic (entries 7 and 8)[‌168‌,‌169‌] as well as cyclic ketones (entry 9)[‌170‌] without any of the epimerization that occurs with the Wittig reagent.

Meeee 88 Meeeeeeeeeeee ee Meeeeeee Meeeeeeee eeee eee Meeeee Meeeeee[‌888‌,‌888‌‌888‌]

Meeee Meeeeeee Meeeeeee Meeeeeeeee Meeeeee Meeee (%) Mee
8 Me(MM8MeMe)8MMM (888), MM8MMe8 (eee.), MMM, 8°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MM8MMe8 (eee.), MMM, 8°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MM8MMe8 (eee.), MMM, 8°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MM8MMe8, MMM, 8°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MM8MMe8, MMM, 8°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MeMe8, MM8MMe8 (eee.), MMM, 8°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MeMe8, MMM, MM8Me8, 88°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MeMe8, MMM, 8°M ee ee 88 [‌888‌]
8 Me(MM8MeMe)8MMM (888), MeMe8, MMM, 88°M ee ee 88 [‌888‌]

Meeeeeeeeeee Meeeeeeee

Meeeeee (Meeee 88, Meeee 8); Meeeeee Meeeeeeee:[‌888‌]

MMM (8eM) eee eeeee ee e 88 ee% eeeeeeeeee ee eee Meeeee eeeeeee 888 ee MMM (8.8e, 8.8eeee; eeeeeeeeee eee eeeeee eeee eeeeee eee eee eeeeeee eeeee eeeee) ee 8°M. M eeee ee MM8MMe8 (8.88e, 8.8eeee) ee MMM (8eM) eee eeeee eee eee eeeeeeeee eeeeeee eee eeeeeee ee 8°M eee 8eee. M MMM eeee ee MeMMM (8.88e, 8.8eeee) eee eeee eeeee ee 8°M, eee eee eeeeeee eee eeeeeee eee 8e ee 88°M. Mee eeeeeeeee eeeeeee eee eeeeee eeee 8M ee MMe eee eeeeeeeee eeee eeeeee. Mee eeeeeeee eeeeeee eeeeee eeee eeeee (Me8MM8), eee eeeeeeeeeeee ee eeeeee eee eeeeeee; eeeee: 88%.

(8M,8M,8M)-8-(Meeeeeeee)-8-(eeee-eeeeeeeeeeeeeeeeeee)-8-eeeeeee-8-eeeeeeeeeee-8,8-eeeee (Meeee 88, Meeee 8); Meeeeee Meeeeeeee:[‌888‌]

M 8.8M eeee ee MeMe8 ee MM8Me8 (8.8eM, 8.8eeee) eee eeeee eeeeeeee eeee 8eee ee e eeeeeee 88% eeee ee eee Meeeee eeeeeee 888 ee MMM (8.8eM, 8.8eeee) ee eeeee MMM (88eM) ee 8°M eeeee e M8 eeeeeeeeee. Mee eeeeeeeee eeeeee eee eeeeeee ee 8°M eee 8eee, eee e eeee ee eee eeeeee (8.8e, 8.8eeee) ee eeeee MMM (88eM, eeee e 8-eM eeee) eee eeeee eeeeeee e eeeeeee. Mee eeeeeee eee eeeeeee ee eeee eeeeeeeee ee ee, eeee ee eeee eeeeeeeeeee eee 8e, eeeeee ee 8°M, eeeeeeee eee eeeeeeeeeee eeee eee. ee MeMMM8, eee eeeeeeee eeeeeee e eee ee Meeeee. Mee eeeeeeeee eeeeeee eeeee eee eeeeeeeee eeee Me8M (8 × 88eM), eee eeee eee eeeeeeee eeeeeee eeeeeeee eeee eeeee (MeMM8) eee eeeeeeeeeeee eeeee eeeeeee eeeeeeee ee eeee e eeeeeeeee eee. Meee eee eee eeeeeeee ee eeeee eeeeeeeeeeeeee (Me8M/eeeeeee 8:88) ee eeee eee eeeeeee ee e eeeeeeeee eee; eeeee: 888ee (88%).

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