Strain-ring construction enabled by boronate complex/1,2-metalate rearrangement
Kanak Kanti Das1, Sutapa Dey2,3
1Universität des Saarlandes, Institut für Organische Chemie, D-66123, Saarbrücken, Germany. kanakiitkgp@gmail.com.
Abstract:
Strain-ring construction represents a longstanding challenge in synthetic organic chemistry due to the substantial energetic penalties associated with forming small and highly constrained ring systems. Over the past decade, 1,2-metalate rearrangement of boronate complexes has emerged as a powerful and unifying strategy to overcome these boundaries. By leveraging the exceptional migratory aptitude of carbon substituents from boron, these rearrangements can actively drive ring contraction via skeletal reorganization even under conditions with increased strain. This review compiles key developments in strain-ring construction triggered by boronate complex/1,2-metalate rearrangement, spanning mono-boronic esters to multi-boron frameworks. The collected studies illustrate how electrophilic, radical, and metal-mediated activation modes can be strategically combined with boron migration to access strained carbocycles and heterocycles with high stereocontrol.
Related Concept Videos
03:08Hydroboration-Oxidation of Alkenes
02:36Regioselectivity and Stereochemistry of Hydroboration
Hydroboration proceeds in a concerted fashion with the attack of borane on the π bond, giving a cyclic four-centered transition state. The –BH2 group is bonded to the less substituted carbon and –H to the more substituted carbon. The concerted nature requires the simultaneous addition of –H and –BH2 across the same face of the alkene giving syn...
02:47Alkynes to Aldehydes and Ketones: Hydroboration-Oxidation
One of the convenient methods for the preparation of aldehydes and ketones is via hydration of alkynes. Hydroboration-oxidation of alkynes is an indirect hydration reaction in which an alkyne is treated with borane followed by oxidation with alkaline peroxide to form an enol that rapidly converts into an aldehyde or a ketone. Terminal alkynes form aldehydes, whereas internal alkynes give ketones as the final product.
02:15Preparation of Alcohols via Addition Reactions
The acid-catalyzed addition of water to the double bond of alkenes is a large-scale industrial method used to synthesize low-molecular-weight alcohols. An acidic atmosphere is required to allow the hydrogen in the water molecule to act as an electrophile and attack the double bond in an alkene. The addition of a proton to the double bond creates a carbocation intermediate. The proton preferentially bonds to the less substituted end of the double bond to create a more stable carbocation...
02:24Acid-Catalyzed Ring-Opening of Epoxides
01:16Olefin Metathesis Polymerization: Ring-Opening Metathesis Polymerization (ROMP)