Formation of Boron Enolates by Nucleophilic Substitution

Abstract

<jats:p>Enolates have proven to be one of the key building blocks available to the synthetic chemist. Here we summarize a novel strategy for their preparation, involving the addition of α-borylated nucleophiles to esters to yield boron enolates. The enolates prepared by the addition of lithiated geminal bis(boron) compounds to esters can be trapped with two equivalents of halogen and alkyl electrophiles to yield α,α-difunctionalized compounds.</jats:p><jats:p>1 Introduction</jats:p><jats:p>2 Ketone Difunctionalization</jats:p><jats:p>3 Boron Enolates by Coupling</jats:p><jats:p>4 Towards Sequential Trapping</jats:p><jats:p>5 Summary and Outlook</jats:p>

Photoinduced catalyst-free borylation of alkenyl triflates with Lewis base complexes of boranes

“…It has been well established that strongly electron-donating substituents on the boron atom normally tend to favour α-boryl carbonyl formation. 4 Thus, many Lewis base-ligated boranes (LB-BH 3 ) 5 have been identified and utilized to access isolable α-borylcarbonyl scaffolds. 6 Among them, transition-metal catalysed direct borylation of α-diazocarbonyl compounds with LB-BH 3 provided a route to α-borylcarbonyl compounds, but the diazo starting materials are difficult to prepare due to safety concerns.…”