Phosphine-catalyzed [3 + 2] and [4 + 2] annulation reactions of ynones with barbiturate-derived alkenes

The phosphine-catalyzed [3 + 2] annulation reaction of ynones and barbiturate-derived alkenes has been developed with the assistance of a weak acid, giving functionalized spirobarbiturate-cyclopentanones in moderate to excellent yields with excellent E/Z stereoselectivity. An unprecedented [4 + 2] a...

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Bibliographic Details
Published in:Organic & biomolecular chemistry 2017-06, Vol.15 (25), p.5298-5307
Main Authors: Gao, Xing, Li, Zhen, Yang, Wenjun, Liu, Yang, Chen, Wufeng, Zhang, Cheng, Zheng, Lufei, Guo, Hongchao
Format: Article
Language:English
Subjects:
Alkenes - chemistry
Barbiturates - chemical synthesis
Barbiturates - chemistry
Catalysis
Cyclopentanes - chemical synthesis
Cyclopentanes - chemistry
Ketones - chemistry
Molecular Structure
Phosphines - chemistry
Spiro Compounds - chemical synthesis
Spiro Compounds - chemistry
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Summary:The phosphine-catalyzed [3 + 2] annulation reaction of ynones and barbiturate-derived alkenes has been developed with the assistance of a weak acid, giving functionalized spirobarbiturate-cyclopentanones in moderate to excellent yields with excellent E/Z stereoselectivity. An unprecedented [4 + 2] annulation of ynones with barbiturate-derived alkenes was also achieved in the presence of a phosphine catalyst and an inorganic base, affording biologically interesting 1,5-dihydro-2H-pyrano[2,3-d]pyrimidine-2,4(3H)-dione derivatives. An asymmetric variant of the [3 + 2] annulation reaction has been explored and a moderate enantioselectivity was obtained when a bifunctional chiral phosphine was used as a chiral catalyst. A plausible mechanism was proposed to illuminate two different reaction pathways.
ISSN:1477-0520
1477-0539
DOI:10.1039/c7ob01034f