383
© Springer Nature Switzerland AG 2021
K. K. Pant et al. (eds.), Catalysis for Clean Energy and Environmental
Sustainability, https://doi.org/10.1007/978-3-030-65017-9_13
C(sp
3
)–H Bond Hetero-functionalization
of Aliphatic Carboxylic Acid Equivalents
Enabled by Transition Metals
Aniket Gupta, Sreedhar Gundekari, and Sukalyan Bhadra
Abstract Aliphatic carboxylic acids and their common derivatives such as amides
and esters, particularly embracing heteroatom-based substituents, are widespread
among natural and synthetic complex molecular frameworks, ratified drugs, and
various tailored materials. Conventional synthetic processes to access these compounds comprise multistep protocols that are virtually inconvenient and unsafe,
generating large mass of wastes within the synthetic sequence. The straightforward
transition metal-catalyzed installation of a heteroatom-based function via transforming a selective C–H bond of an aliphatic carboxylic acid equivalent has recently
materialized as an attractive substitute to those multistep processes. In the latter
case, the carboxylate group, either directly or in the form of an interconvertible
directing group, controls the highly selective metal-promoted heterofunctionalization process in the alkyl chain residue through extraordinarily ordered
transition states.
The current chapter summarizes the advances in the field of transition metalenabled C(sp
3
)–H bond hetero-functionalization of aliphatic carboxylic acids and
their synthetic equivalents. Due to substantial progress in recent years, only frequently employed transition metals, including palladium, nickel, copper, iron, and
cobalt, which promoted reactions have been described. The chapter has been divided
into two key subtopics: (1) directed C(sp
3
)–H hetero-functionalization approaches,
in which the carboxylic acid or a promptly adaptable carboxylate equivalent actively
binds to the metal catalyst and brings it close to the cleavable C(sp
3
)–H bond to
facilitate further functionalization, and (2) non-directed C(sp
3
)–H heterofunctionalization approaches, in which the carboxylic acid equivalents passively
control the metal-promoted C(sp
3
)–H functionalization. Gratifyingly, both
approaches lead to regiospecific functionalization of carboxylic acid synthons at
either proximal-selective α-C–H bonds or distal β-, γ-, and even δ-C–H bonds with
A. Gupta · S. Gundekari · S. Bhadra (*)
Inorganic Materials and Catalysis Division, Academy of Scientific and Innovative Research
(AcSIR), Ghaziabad, India
CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India
e-mail: sbhadra@csmcri.res.in
© Springer Nature Switzerland AG 2021
K. K. Pant et al. (eds.), Catalysis for Clean Energy and Environmental
Sustainability, https://doi.org/10.1007/978-3-030-65017-9_13
C(sp
3
)–H Bond Hetero-functionalization
of Aliphatic Carboxylic Acid Equivalents
Enabled by Transition Metals
Aniket Gupta, Sreedhar Gundekari, and Sukalyan Bhadra
Abstract Aliphatic carboxylic acids and their common derivatives such as amides
and esters, particularly embracing heteroatom-based substituents, are widespread
among natural and synthetic complex molecular frameworks, ratified drugs, and
various tailored materials. Conventional synthetic processes to access these compounds comprise multistep protocols that are virtually inconvenient and unsafe,
generating large mass of wastes within the synthetic sequence. The straightforward
transition metal-catalyzed installation of a heteroatom-based function via transforming a selective C–H bond of an aliphatic carboxylic acid equivalent has recently
materialized as an attractive substitute to those multistep processes. In the latter
case, the carboxylate group, either directly or in the form of an interconvertible
directing group, controls the highly selective metal-promoted heterofunctionalization process in the alkyl chain residue through extraordinarily ordered
transition states.
The current chapter summarizes the advances in the field of transition metalenabled C(sp
3
)–H bond hetero-functionalization of aliphatic carboxylic acids and
their synthetic equivalents. Due to substantial progress in recent years, only frequently employed transition metals, including palladium, nickel, copper, iron, and
cobalt, which promoted reactions have been described. The chapter has been divided
into two key subtopics: (1) directed C(sp
3
)–H hetero-functionalization approaches,
in which the carboxylic acid or a promptly adaptable carboxylate equivalent actively
binds to the metal catalyst and brings it close to the cleavable C(sp
3
)–H bond to
facilitate further functionalization, and (2) non-directed C(sp
3
)–H heterofunctionalization approaches, in which the carboxylic acid equivalents passively
control the metal-promoted C(sp
3
)–H functionalization. Gratifyingly, both
approaches lead to regiospecific functionalization of carboxylic acid synthons at
either proximal-selective α-C–H bonds or distal β-, γ-, and even δ-C–H bonds with
A. Gupta · S. Gundekari · S. Bhadra (*)
Inorganic Materials and Catalysis Division, Academy of Scientific and Innovative Research
(AcSIR), Ghaziabad, India
CSIR-Central Salt and Marine Chemicals Research Institute, Bhavnagar, Gujarat, India
e-mail: sbhadra@csmcri.res.in