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Daniel FL, Srinivasan K. Intramolecular 1,2-Aroyl Migration in Spiro Donor-Acceptor Cyclopropanes: Formation of 1,4-Naphthoquinones and 1-Naphthols as Ring-Expansion Products. J Org Chem 2024; 89:5304-5313. [PMID: 38593430 DOI: 10.1021/acs.joc.3c02671] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 04/11/2024]
Abstract
Most of the known rearrangement reactions of donor-acceptor cyclopropanes (DACs) involve the migration of cationic carbon atom to anionic carbon or heteroatoms in 1,3- or 1,4-positions. In the present work, we observed that spiro DACs based on 1,3-indanedione or 1-indanone moiety undergo intramolecular 1,2-aroyl migration when treated with titanium(IV) chloride to afford 1,4-naphthoquinones and α-naphthols readily. The reactions take place through the formation of putative 1,3-dipolar intermediates, followed by cleavage and migration of the aroyl group to the adjacent carbon to afford the ring-expansion products.
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Affiliation(s)
- Franklin Leslin Daniel
- School of Chemistry, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620 024, India
| | - Kannupal Srinivasan
- School of Chemistry, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620 024, India
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Thangamalar S, Srinivasan K. Tandem Dearomative/Rearomative (3 + 2) Annulation of Aroyl-Substituted Donor-Acceptor Cyclopropanes with Benzothiazoles. J Org Chem 2023; 88:3903-3908. [PMID: 36877197 DOI: 10.1021/acs.joc.2c02768] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/07/2023]
Abstract
A series of benzo[d]pyrrolo[2,1-b]thiazoles was synthesized by (3 + 2) annulation of aroyl-substituted donor-acceptor cyclopropanes with benzothiazoles. The annulation, promoted by a substoichiometric amount of Sc(OTf)3, takes place through the formation of the respective dearomatized (3 + 2) adducts, followed by unexpected decarbethoxylative and dehydrogenative rearomatization to afford fully aromatized products. The unusual reactivity is attributed to the presence of an extra aroyl group in the donor-acceptor cyclopropanes.
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Affiliation(s)
| | - Kannupal Srinivasan
- School of Chemistry, Bharathidasan University, Tiruchirappalli, Tamil Nadu 620 024, India
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Singh PR, Gopal B, Kumar M, Goswami A. A metal-free BF 3·OEt 2 mediated chemoselective protocol for the synthesis of propargylic cyclic imines. Org Biomol Chem 2022; 20:4933-4941. [PMID: 35648486 DOI: 10.1039/d2ob00530a] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
A chemoselective and metal/additive-free protocol for the synthesis of propargylic cyclic imine derivatives via (3 + 2)-cycloaddition of donor-acceptor cyclopropanes and alkynylnitriles in the presence of BF3·OEt2 has been established. The newly developed methodology provided access to a variety of propargylic cyclic imines in good to excellent yields. In addition, the synthesis of propargylic amines and the corresponding very stable enol derivatives from the title compound is also explored.
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Affiliation(s)
- Prasoon Raj Singh
- Department of Chemistry, Indian Institute of Technology Ropar, SS Bhatnagar Block, Main Campus, Rupnagar, Punjab-140001, India.
| | - Braj Gopal
- Department of Chemistry, Indian Institute of Technology Ropar, SS Bhatnagar Block, Main Campus, Rupnagar, Punjab-140001, India.
| | - Madan Kumar
- Department of Chemistry, Indian Institute of Technology Ropar, SS Bhatnagar Block, Main Campus, Rupnagar, Punjab-140001, India.
| | - Avijit Goswami
- Department of Chemistry, Indian Institute of Technology Ropar, SS Bhatnagar Block, Main Campus, Rupnagar, Punjab-140001, India.
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Vartanova AE, Plodukhin AY, Ratmanova NK, Andreev IA, Anisimov MN, Gudimchuk NB, Rybakov VB, Levina II, Ivanova OA, Trushkov IV, Alabugin IV. Expanding Stereoelectronic Limits of endo- tet Cyclizations: Synthesis of Benz[ b]azepines from Donor-Acceptor Cyclopropanes. J Am Chem Soc 2021; 143:13952-13961. [PMID: 34406759 DOI: 10.1021/jacs.1c07088] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
The importance of intramolecular constraints in cyclic transition-state geometries is especially pronounced in n-endo-tet cyclizations, where the usual backside approach of a nucleophile to the breaking bond is impossible for the rings containing less than eight atoms. Herein, we expand the limits of endo-tet cyclizations and show that donor-acceptor cyclopropanes can provide a seven-membered ring via a genuine 6-endo-tet process. Substrates containing a N-alkyl-N-arylcarbamoyl moiety as an acceptor group undergo Lewis acid-induced cyclization to form tetrahydrobenz[b]azepin-2-ones in high yields. The reaction proceeds with the inversion of the configuration at the electrophilic carbon. In this process, a formally six-membered transition state yields a seven-membered ring as the pre-existing cycle is merged into the forming ring. The stereochemistry of the products can be controlled by the reaction time and by the nature of Lewis acid, opening access to both diastereomers by tuning of the reaction conditions.
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Affiliation(s)
- Anna E Vartanova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119334, Russian Federation.,Faculty of Science, RUDN University, Moscow 117198, Russian Federation
| | - Andrey Yu Plodukhin
- Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Nina K Ratmanova
- Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology, Moscow 117997, Russian Federation
| | - Ivan A Andreev
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119334, Russian Federation.,Dmitry Rogachev National Medical Research Center of Pediatric Hematology, Oncology, and Immunology, Moscow 117997, Russian Federation
| | - Mikhail N Anisimov
- Department of Physics, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation.,Center for Theoretical Problems of Physicochemical Pharmacology, Moscow 119334, Russian Federation
| | - Nikita B Gudimchuk
- Department of Physics, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation.,Center for Theoretical Problems of Physicochemical Pharmacology, Moscow 119334, Russian Federation
| | - Victor B Rybakov
- Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Irina I Levina
- Institute of Biochemical Physics, Russian Academy of Sciences, Moscow 119334, Russian Federation
| | - Olga A Ivanova
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119334, Russian Federation.,Department of Chemistry, M. V. Lomonosov Moscow State University, Moscow 119991, Russian Federation
| | - Igor V Trushkov
- N. D. Zelinsky Institute of Organic Chemistry, Russian Academy of Sciences, Moscow 119334, Russian Federation
| | - Igor V Alabugin
- Department of Chemistry and Biochemistry, Florida State University, Tallahassee, Florida 32306-4390 United States
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