Catalytic reductive carbene transfer reactions

Catalytic Diastereo‐ and Enantioselective Cyclopropanation of gem‐Dihaloalkanes and Terminal Olefins

“…As aforementioned, developing asymmetric carbene transfer reactions of diazo reagents without stabilizing groups is a formidable challenge [9a] . To tackle this problem via a reductive carbene transfer, we tested the reaction of (3,3‐dichloropropyl)benzene and 2 a under optimal conditions.…”

“…gem-Dihaloalkanes are readily available, bench-stable, and thus highly complementary to unstable diazo alkanes in carbene transfer reactions. [9] As demonstrated in the classical Simmons-Smith reaction, the cyclopropanation between olefins and diiodomethane was achieved via a plausible zinc carbenoid intermediate. [6a,b] In this context, a series of elegant methods have been developed to access racemic cyclopropanes, using stoichiometric metal reagents, [10,11] transition-metal catalysis, [12] or photoredox catalysis, [13] which demonstrate the feasibility of using gem-dihaloalkanes as surrogates for unstabilized diazo alkanes (Figure 1b).…”

“…Among these, the chromium‐catalyzed cyclopropanations of heteroatom‐substituted gem ‐diiodomethane and olefins are noteworthy, which achieve facile diastereoselectivity control despite excessively relying on reactive diiodoalkanes [10b, 12a] . However, the modular catalytic enantioselective cyclopropanation of gem ‐dichloro‐ or gem ‐dibromoalkanes and olefins remains elusive, which could greatly expand the chemical space of valuable cyclopropanes and thus is in high demand [9a, 14] …”

Fe-catalyzed B–H and Si–H insertion reactions of gem-dihaloalkanes

“…The exploration of non-stabilized carbene precursors in catalytic B-H insertion reactions is imperative to expand the chemical space of organoboranes, addressing a significant demand. 13 Gem-dihaloalkanes are readily available and have proven to be excellent non-stabilized carbene precursors in carbene transfer reactions, 14 exemplified by the Simmons-Smith reaction 15 and Takai olefinations. 16 Recent elegant work by the Uyeda group showcased the applicability of gem-dichloroalkanes in cyclopropanations and cycloaddition reactions catalyzed by Co or Ni.…”

Light induced diversity-oriented synthesis (DOS) library of annulated indolizine fluorophores for imaging non-lysosomal lipid droplets (LDs)

“…20 During the last few years, photochemical carbene generation and subsequent transformation paved an efficient way for organic chemists to access a diverse range of heterocycles. [21][22][23][24][25][26][27] Among them, multicomponent reactions involving the in situ generation of carbenes and ylides have gained importance as robust singlestep strategies involving mild reaction conditions to construct structurally diverse scaffolds of biological significance. [28][29][30] Herein, we report the development of a library of annulated fluorescent indolizine compounds via a systematic structure-photophysical property relationship (SPPR) study.…”