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Chemical reduction of highly-twisted 9,10,11,20,21,22-hexaphenyltetrabenzo[a,c,l,n]pentacene (C74H46, 1) was investigated using Li and Cs metals as the reducing agents. The Cs-induced reduction of 1 in the presence of 18-crown-6 ether enabled the isolation of a solvent-separated ion pair (SSIP) with a “naked” monoanion. Upon reduction with Li metal, a double reductive dehydrogenative annulation of 1 was observed to afford a new C74H422– dianion. The latter was shown to undergo a further reduction to C74H424– without additional core transformation. All products were characterized by single-crystal X-ray diffraction and spectroscopic methods. Subsequent in-depth theoretical analysis of one vs. two and four electron uptake by 1 provided insights into how the changes of geometry, aromaticity and charge facilitated the core transformation of twistacene observed upon two-fold reduction. These experimental and theoretical results pave the way to understanding of the reduction-induced core transformations of highly twisted and strained π-systems.
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Functional Group Interconversion of Alkylidenemalononitriles to Primary Alcohols by a Cooperative Redox Operation
Functional group interconversions are essential chemical processes enabling synthesis. In this report, we describe a strategy to convert alkylidenemalononitriles into primary alcohols in one step. The reaction relies on a choreographed redox process involving alkylidene reduction, malononitrile oxidation, and acylcyanide reduction where molecular oxygen and NaBH4 work cooperatively. The method was applied to a variety of carbon skeletons and was utilized to synthesize complex terpenoid architectures.
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- Award ID(s):
- 1844443
- PAR ID:
- 10224437
- Date Published:
- Journal Name:
- Synthesis
- Volume:
- 52
- ISSN:
- 0039-7881
- Page Range / eLocation ID:
- 3077 - 3085
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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- Free Publicly Accessible Full Text
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Accepted Manuscript1.0
- Journal Article:
- https://doi.org/10.1055/s-0040-1707184
