@article {49275, title = {Strategies employing transition-metal free conditions for C-C bond formation in indoles}, journal = {ChemistrySelect}, volume = {9}, year = {2024}, month = {SEP}, pages = {e202403280}, type = {Review}, abstract = {

Indole motifs are omnipresent in nature and can be found in many natural products as well as pharmaceuticals. It is for this reason synthetic transformations of indole have become a topic of interest for the organic and medicinal chemist community for decades. In this review, we have emphasized the functionalization of indoles via transition-metal-free approaches. This review touches on many aspects in different sub-sections, which gives a proposition of the tactics employed for the functionalization of indoles and an overview of the road ahead. In this review, essentially transition-metal-free conditions for C-C bond formation reactions in indoles has been explored. This review describes various approaches of functionalization at the C-2, C-3, C-4 and C-7 position of indoles which comprises arylation, alkenylation, acylation, formylation, alkylation, bisindolyl and cyclization strategies. Also, strategies incorporating N-alkylation/arylation has also been covered. image

}, keywords = {Alkylation, Arylation, formylation, Indole, transition-metal free}, issn = {2365-6549}, doi = {10.1002/slct.202403280}, author = {Ghodake, Balaji M. and Paul, Sayantan and Bhattacharya, Asish K.} } @article {49510, title = {Catalyst and transition-metal free 1,6-conjugate addition of azobisisobutyronitrile: access to isobutyronitrile containing diarylmethanes}, journal = {Organic \& Biomolecular Chemistry}, volume = {23}, year = {2025}, month = {APR}, pages = {3956-3966}, type = {Article}, abstract = {

A catalyst and transition-metal free 1,6-conjugate addition of azobisisobutyronitrile to para-quinone methides for the synthesis of isobutyronitrile containing diarylmethanes has been achieved. This protocol enables the synthesis of isobutyronitrile containing diarylmethanes in good yields and with a broad substrate scope. This is the first example wherein azobisisobutyronitrile has been used as a cyanide source for 1,6-conjugate addition under catalyst and metal-free conditions.

}, issn = {1477-0520}, doi = {10.1039/d5ob00012b}, author = {Mamale, Ajay G. and Ghodake, Balaji M. and Gonnade, Rajesh G. and Bhattacharya, Asish K.} } @article {50127, title = {One-pot synthesis of N-arylated benzotriazoles and benzotriazinones via in situ diazotization and aryne trapping}, journal = {Organic \& Biomolecular Chemistry}, volume = {24}, year = {2026}, month = {JUN}, pages = {4696-4711}, type = {Article}, abstract = {

N-Arylated benzotriazoles and 1,2,3-benzotriazin-4-ones are important structural motifs in synthetic and medicinal chemistry, valued for their distinctive frameworks and functional versatility. We have developed an efficient, one-pot strategy for the synthesis of N-arylated benzotriazoles and benzotriazinones. The protocol involves in situ diazotization of o-phenylenediamine or 2-aminobenzamide using tert-butyl nitrite (tBuONO), followed by trapping of arynes generated in situ from 2-(trimethylsilyl)aryltriflates in the presence of CsF. The methodology exhibits broad functional-group tolerance and was successfully applied to 47 substrates, affording yields in the range of 60-85\%. Furthermore, gram-scale synthesis highlights the operational simplicity and practical utility of this approach.

}, issn = {1477-0520}, doi = {10.1039/d6ob00648e}, author = {Ghodake, Balaji M. and Bhattacharya, Asish K.} }