Stereodivergent 1,3-difunctionalization of alkenes by charge relocation

Abstract

Alkenes are indispensable feedstocks in chemistry. Functionalization at both carbons of the alkene—1,2-difunctionalization—is part of chemistry curricula worldwide1. Although difunctionalization at distal positions has been reported2–4, it typically relies on designer substrates featuring directing groups and/or stabilizing features, all of which determine the ultimate site of bond formation5–7. Here we introduce a method for the direct 1,3-difunctionalization of alkenes, based on a concept termed ‘charge relocation’, which enables stereodivergent access to 1,3-difunctionalized products of either syn- or anti-configuration from unactivated alkenes, without the need for directing groups or stabilizing features. The usefulness of the approach is demonstrated in the synthesis of the pulmonary toxin 4-ipomeanol and its derivatives.

Efficient synthesis of benzophosphole oxides via Ag-promoted radical cycloisomerization

“…This work also highlights the synthetic potential of silver salts. Long neglected compared to other TM, Ag I species have found increasing applications as π-activators, halide abstractors 38 as well as oxidants. 39 In this work, AgSbF 6 was used as a radical initiator, in catalytic amounts and without any external oxidant.…”

Alkene 1,3‐Difluorination via Transient Oxonium Intermediates

“…The 1,3-difunctionalization of alkenes is a more unusual transformation that provides a route towards interesting remotely functionalized moieties, [35][36][37][38][39][40][41][42][43] Figure 1B. Metalhydride intermediates positionally isomerize alkenes, which has led to the development of metal-catalyzed strategies.…”

Stereoselective Three-Component Carbocyclization of 1,7-Enynes with Sulfoxonium Ylides and Water under Photoredox Catalysis

“…Subsequently, the reductive single-electron-transfer (SET) of intermediate F with the oxidation state of [Ir IV ] afforded the carbon radical cation intermediate G , along with the generation of the ground state [Ir III ] catalyst. The cyclic oxocarbenium ion H was generated via a rapid locking event, which could effectively prevent further isomerization and nonselective product formation . Ultimately, intermediate H was attacked by nucleophilic H 2 O and deprotonation to deliver cyclopenta[ c ]quinoline molecule 3a with excellent chemoselectivities and stereoselectivities.…”