Henan Key Laboratory of Organic Functional Molecules and Drug Innovation, Collaborative Innovation Center of Henan Province for Green Manufacturing of Fine Chemicals, School of Chemistry and Chemical Engineering, Henan Normal University, Xinxiang, Henan 453007, China.
Chem Commun (Camb). 2019 Jan 31;55(11):1580-1583. doi: 10.1039/c8cc09595g.
The Yb(OTf)3-catalyzed [3+2] cycloaddition of donor-acceptor cyclopropanes with thiourea offers an efficient route to diverse 2-amino-4,5-dihydrothiophenes (up to 92% yield), in which optically active 2-amino-dihydrothiophenes can be produced from enantiomerically pure cyclopropanes. Thiourea, which is an odorless and cheap reagent, provides a C[double bond, length as m-dash]S double bond, serves as an amino source, and functions as a decarbalkoxylation reagent in this reaction. Preliminary mechanistic studies demonstrate that the reaction undergoes a sequential [3+2] cycloaddition/deamination/decarboxylation process.
Yb(OTf)3 催化给体-受体环丙烷与硫脲的 [3+2]环加成反应为合成各种 2-氨基-4,5-二氢噻吩提供了一条有效途径（最高产率达 92%），其中，旋光纯环丙烷可用于合成光学活性的 2-氨基二氢噻吩。硫脲作为一种无味且廉价的试剂，提供了一个 C[双键，长度 as m-dash]S 双键，同时充当氨基源，并在反应中起到脱羧基化试剂的作用。初步的机理研究表明，该反应经历了一个顺序的[3+2]环加成/脱氨/脱羧过程。
