2.06 Formation of Enolates

Enabling Cyclization Strategies through Carbonyl-Ylide-Mediated Synthesis of Malonate Enol Ethers

“…With α-methyl and α-phenyl groups, trisubstituted enol ethers 3pA and 3qA were formed preferentially (rr 9:1, 66–74%). 47 Such regioselectivity forming the so-called kinetic enol geometry 48 was obtained exclusively for bromo derivative 3rA (47%, rr > 24:1), the structure of which being confirmed by X-ray diffraction analysis ( Scheme 3 ). Interestingly, in the solid state and most probably in solution ( 1 H NMR spectroscopy), the bromine atom assumes a pseudoaxial position due to a minimization of the allylic 1,2-strain.…”

SmI2‐mediated C‐alkylation of Ketones with Alcohols under Microwave Conditions: A Novel Route to Alkylated Ketones

“…Traditional methods involve reaction between nucleophilic metal enolate of carbonyl compound and electrophilic halides as alkylating agents. [2] In addition, various transition metal-catalyzed cross-coupling reactions are reported towards the construction of CÀ C bond (Scheme 1). [3] However, these methods require environmentally unfriendly mutagenic halides, expensive organometallic reagents and stoichiometric amounts of bases, thereby, generating large amount of waste.…”

Experimental and Computational Evidence of the Biradical Structure and Reactivity of Titanium(IV) Enolates

“…Metal enolates play a crucial role in a wide range of carbon–carbon as well as carbon–heteroatom bond forming reactions and are therefore among the most important nucleophilic species in organic synthesis. − Alkylation or aldol reactions are well-known examples of the sort of transformations that hinge on the enolization of a parent carbonyl compound and the reactivity of the resultant enolate. − Therefore, great effort has been dedicated to the development of increasingly more efficient enolization procedures that supply metal enolates capable of participating in highly selective reactions . As a result of such research, a handful of procedures have emerged as the most appropriate to obtain metal enolates with remarkable regio- and stereocontrol, which can subsequently react with a broad range of electrophiles under a variety of mild conditions .…”