Fuchs-Corey method

Scientists at DuPont Merck Pharmaceuticals [31] had also developed a new process to prepare 37, based on a modification of the Corey-Fuchs method, from cyclopropylaldehyde, prepared by thermal rearrangement of butadiene monoxide. 

The reaction sequence in steps two and three is known as the Corey-Fuchs method to create an alkyne from an aldehyde 10 Reaction of triphenylphosphane with carbontetrabromide gives phenylphosphane-dibromomethylene. This reagent then transforms aldehyde 19 into the corresponding dibromoalkene 20 thereby extending the chain by one carbon. Reaction of the bromo compound with two equivalents of n-butyllithium in THF at -78 °C results in the rapid formation of the acetylenic lithio derivative which forms the terminal acetylene 21 upon aqueous work-up. 

Ene-yne metathesis has been employed in an elegant synthesis of stemoamide 8.415 (Scheme 8.112). The starting lactam 8.407, available itself from glutamic acid, was iV-alkylated, then subjected to deprotection, Swern oxidation and application of the Corey-Fuchs method for installation of an alkyne by Wittig... 

The synthesis of the novel achiral host material can be achieved in a variety of ways. Using the Corey-Fuchs method, which involves a modified Wittig reaction of 4-alkoxybenzaldehydes with carbon tet-rabromide, phenylpropiolic acids can be prepared by lithiation and treatment with solid carbon dioxide (see center of Fig. 42). Alternatively, this can also be achieved using a palladium(O) mediated coupling between 3-methyl-3-hydroxybutyne and an... 

Another common method for the conversion of an aldehyde into an alkyne is the transformation of the aldehyde via a Corey-Fuchs reaction into a geminal vinyl dibromide followed by reaction with nbutyllithium and aqueous work-up.22... 

Corey-Fuchs reaction followed by palladium-catalyzed debro-mination with BusSnH also gives Z-alkenyl bromide selectively (eq 7). This two-step method has been used successfully in many syntheses of natural products like morphine by Trost and cephalostatin analogues by Tietze. ... 

Corey, E. J., Fuchs, P. L. Synthetic method for conversion of formyl groups into ethynyl groups (RCHO -> RCCH or RCCR1). Tetrahedron Lett. 1972, 3769-3772. 

Corey EJ, Fuchs PL (1972) Synthetic Method for Conversion of Formyl Groups into Ethynyl Groups. Tetrahedron Lett 36 3769... 

Corey, E.J., and P.L. Fuchs A Synthetic Method for Formyl - Ethynyl conversion. Tetrahedron Lett. 1972, 3769. 

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