Masked alcohols are particularly appealing as directing groups because of the ubiquity of hydroxy groups in organic small molecules. Herein, we disclose a general strategy for aliphatic γ-C(sp )-H functionalization guided by a masked alcohol. Specifically, we determine that sulfamate ester derived nitrogen-centered radicals mediate 1,6-hydrogen-atom transfer (HAT) processes to guide γ-C(sp )-H chlorination. This reaction proceeds through a light-initiated radical chain-propagation process and is capable of installing chlorine atoms at primary, secondary, and tertiary centers.

A general approach to access sulfamate esters through preparation of sulfamic acid salts, subsequent activation with triphenylphosphonium ditriflate, and nucleophilic trapping is disclosed. The method proceeds in modest to excellent yields to incorporate nucleophiles derived from aliphatic alcohols and phenols. This approach can be employed to furnish differentially substituted sulfamides.

Masked alcohols are particularly appealing as directing groups because of the ubiquity of hydroxy groups in organic small molecules.H erein, we disclose ag eneral strategy for aliphatic g-C(sp 3 )ÀHf unctionalization guided by am asked alcohol. Specifically,w ed etermine that sulfamate ester derived nitrogen-centered radicals mediate 1,6-hydrogenatom transfer (HAT) processes to guide g-C(sp 3 ) À Hchlorination. This reaction proceeds through al ight-initiated radical chain-propagation process and is capable of installing chlorine atoms at primary,secondary,and tertiary centers. Angewandte ChemieCommunications 297

Nitrogen-centered radicals are powerful reaction intermediates owing in part to their ability to guide position-selective C(sp3)–H functionalization reactions. Typically, these reactive species dictate the site of functionalization by preferentially engaging in 1,5-hydrogen-atom transfer (1,5-HAT) processes. Broadly relevant approaches to alter the site-selectivity of HAT pathways would be valuable because they could be paired with a variety of tactics to install diverse functional groups. Yet, until recently, there have been no generalizable strategies to modify the position-selectivity observed in these HAT processes. This Synpacts article reviews transformations in which nitrogen-centered radicals preferentially react through 1,6-HAT pathways. Specific attention will be focused on strategies that employ alcohol- and amine-anchored sulfamate esters and sulfamides as templates to achieve otherwise rare γ-selective functionalization reactions.1 Introduction2 Transformations that Rely on Structural Constraints or Weakened C–H Bonds to Favor 1,6-HAT Processes3 Sulfamate Esters Engage Selective 1,6-HAT Processes4 Expansion to 1,6-HAT Processes with Masked Amine Substrates5 Conclusions and Outlook

Amine-anchored sulfamides direct radical-mediated chlorination of aliphatic C–H bonds. The site of C–H abstraction can be modulated by varying the sulfamide nitrogen substituents, a feature that has not been demonstrated with other substrate classes.