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The cyclopropyl group is of great importance in medicinal chemistry, as it can be leveraged to influence a range of pharmaceutical properties in drug molecules. This report describes a Vitamin B₁₂‐photocatalyzed approach for the cyclopropanation of electron‐deficient alkenes using dichloromethane (CH₂Cl₂) as the methylene source. The reaction proceeds in good to excellent yields under mild conditions, has excellent functional group compatibility, and is highly chemoselective. The scope could also be extended to the preparation of D₂‐cyclopropyl and methyl‐substituted cyclopropyl adducts starting from CD₂Cl₂and 1,1‐dichloroethane, respectively.

 

The cyclopropyl group is of great importance in medicinal chemistry, as it can be leveraged to influence a range of pharmaceutical properties in drug molecules. This report describes a Vitamin B₁₂‐photocatalyzed approach for the cyclopropanation of electron‐deficient alkenes using dichloromethane (CH₂Cl₂) as the methylene source. The reaction proceeds in good to excellent yields under mild conditions, has excellent functional group compatibility, and is highly chemoselective. The scope could also be extended to the preparation of D₂‐cyclopropyl and methyl‐substituted cyclopropyl adducts starting from CD₂Cl₂and 1,1‐dichloroethane, respectively.

 

Exploiting charge-transfer complexes in visible light-promoted single-electron redox reactions is a promising route for opening novel synthetic pathways, and catalytic approaches to complex formation are critical for facilitating this chemistry. This report describes the use of a substituted hydroquinone catalyst to promote radical perfluoroalkylation reactions. Mechanistic studies indicate that the reaction is initiated through formation of a visible light-absorbing halogen bonding complex between the hydroquinone catalyst and the perfluoroalkyl halide radical precursor. 

Recent progress in the development of photocatalytic reactions promoted by 5 visible light is leading to a renaissance in the use of photochemistry in the construction of 6 structurally elaborate organic molecules. Because of the rich functionality found in natural 7 products, studies in natural product total synthesis provide useful insights into functional 8 group compatibility of these new photocatalytic methods as well as their impact on synthetic 9 strategy. In this review, we examine total syntheses published through the end of 2020 that 10 employ a visible-light photoredox catalytic step. To assist someone interested in employing 11 the photocatalytic steps discussed, the review is organized largely by the nature of the bond 12 formed in the photocatalytic step.