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DOI: 10.1055/sos-SD-047-00100

Petasis, N. A.Science of Synthesis, (201047183.

Ketones are excellent substrates for carbonyl methylenation with the Petasis reagent 37. This process often works very well even in transformations that are not very efficient with the Wittig or Tebbe reagents. Several examples of this sort are listed in Table 9,[‌60‌,‌61‌,‌63‌,‌78‌‌84‌] including the methylenation of readily enolizable ketones (entries 13),[‌60‌,‌61‌,‌78‌]) and enones (entries 4 and 5).[‌60‌,‌79‌] Ketones are generally methylenated preferentially over esters (entry 6),[‌60‌] thioesters (entry 7),[‌80‌] or vinylogous esters (entry 8),[‌63‌] even though all these carbonyl species can also be methylenated (for an example of methylenation of a vinylogous ester, see entry 9).[‌81‌] Methylenation proceeds efficiently in the presence of an unprotected hydroxy group (entry 10),[‌82‌] while reaction of (S)-2-[(tert-butyldiphenylsiloxy)methyl]-1-tosylazetidin-3-one gives the expected product (entry 11)[‌83‌] even though the Wittig reagent fails completely in this process due to substrate fragmentation. The Petasis reagent 37 is also a very efficient reagent for the methylenation of a piperidinone derivative (entry 12).[‌84‌]

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8 Me(Me)8(Me)8 (88), MMM, 88°M 88 [‌88‌]
8 Me(Me)8(Me)8 (88), eeeeeee, MMM, 88°M, 88e 88 [‌88‌]
8 Me(Me)8(Me)8 (88), eeeeeee, MMM, 88°M 88 [‌88‌]
8 Me(Me)8(Me)8 (88), MMM, 88°M, 88e 88 [‌88‌]
8 Me(Me)8(Me)8 (88; 8 eeeee), eeeeeee, MMM, 88°M 88 [‌88‌]
8 Me(Me)8(Me)8 (88), e-MeMM8Me, MMM, 88°M 88 [‌88‌]
8 Me(Me)8(Me)8 (88), MMM, 88°M 88 [‌88‌]
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88 Me(Me)8(Me)8 (88), eeeeeee, 888°M, 8e 88 [‌88‌]
88 Me(Me)8(Me)8 (88), eeeeeee, 88°M, 88e 88 [‌88‌]
88 Me(Me)8(Me)8 (88; 8.8 eeeee), MMM, 88°M, 8e 88 [‌88‌]

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(8eM,8M,8eM)-8,8-Meeeeeee-8-eeeeeeeee-8-[(eeeeeeeee)eeeeee]eeeeeeeeee-8M-eeeeeeeeee[e][8,8]eeeeeee (Meeee 8, Meeee 8); Meeeeee Meeeeeeee:[‌88‌]

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(8M,8M)-8-(Meeeeeeeeeeeeee)-8-eeeeeeeee-8-eeeeee-8-eeeeeeeeeeeeeeeeeeee (Meeee 8, Meeee 8); Meeeeee Meeeeeeee[‌88‌]

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