Photoinduced Regioselective Olefination of Arenes at Proximal and Distal Sites

Abstract

The Fujiwara-Moritani reaction has had a profound contribution in the emergence of contemporary C-H activation protocols. Despite the applicability of the traditional approach in different elds, the associated reactivity and regioselectivity issues had rendered it redundant. The revival of this exemplary reaction requires the development of a mechanistic paradigm that would have simultaneous control on both the reactivity and regioselectivity. Often high thermal energy required to promote ole nation leads to multiple site functionalization. To this aim we established a photoredoxcatalytic system constituting a merger of palladium/organo-photocatalyst that forges oxidative ole nation in an explicit regioselective fashion of diverse arenes and heteroarenes. Visible light plays a signi cant role in executing 'regio-resolved' Fuijiwara-Moritani reaction without the requirement of silver salts and thermal energy. The catalytic system is also amenable towards proximal and distal ole nation aided by respective directing groups (DGs), which entails the versatility of the protocol in engaging the entire spectrum of C(sp2)-H ole nation.Furthermore, streamlining the synthesis of natural products, chiral molecules, drugs and diversi cation through late-stage functionalizations underscore the importance of this sustainable protocol. The photoinduced attainment of this regioselective transformation is mechanistically established through control reactions, kinetic studies and theoretical calculations.

Dual Palladium‐Photoredox Catalyzed C−H functionalization

“…The following mechanism was proposed by the Rueping group as shown in Scheme Recently, Maiti et al reported regioselective Fujiwara-Moritani reaction via merging photoredox catalysis with Pd catalysis under O 2 environment employing Eosin Y as photocatalyst. [32] They first demonstrated olefination of arenes through a nondirected approach. A broad number of acrylate derivatives smoothly underwent this reaction as olefin surrogates.…”

“…Recently, Maiti et al. reported regioselective Fujiwara‐Moritani reaction via merging photoredox catalysis with Pd catalysis under O 2 environment employing Eosin Y as photocatalyst [32] . They first demonstrated olefination of arenes through a non‐directed approach.…”

Transition-metal-catalyzed C–H bond alkylation using olefins: recent advances and mechanistic aspects

“…In the past few decades, the development of C-H functionalization reactions that enable the construction of fundamentally important C-C and C-X bonds has witnessed tremendous upsurge. [1][2][3][4][5][6][7][8][9][10][11] Within the domain, transition metal catalysis forms the largest, ever expanding subset contributing to the broad spectrum of applications that ranges from organic synthesis to petrochemical processing. [12][13][14][15][16][17][18][19][20] In this context, the development of novel methods to access arylation, [21][22][23][24] alkenylation [25][26][27] and alkynylation of C-H bonds 28 has gained tremendous attention.…”

Pd(ii)-catalyzed meta-C–H bromination and chlorination of aniline and benzoic acid derivatives

“…8 a However, the meta -C–H halogenation of anilines is still a formidable challenge since the conventional highly reactive sites are ortho / para positions. Although there have been several significant strategies disclosed for meta -C–H functionalization of arenes 9–28 and a few of them have been applied for aniline derivatives by the groups of Gaunt, 10 Yu, 11 Ackermann, 12 Phipps, 13 a Nakao, 14 and others 15 as well as our group, 16 to date, only a single 29 report on meta -C–H halogenation ( i.e. chlorination) of aniline derivatives has been disclosed by the Yu group using a substituted pyridine as the DG for the initial ortho -C–H activation and modified norbornene as the mediator for subsequent meta -C–H chlorination (Scheme 1b).…”