Synthesis of 3,4-Dihydro-2H-1,3-thiazines from α-Enolic Dithioesters and 1,3,5-Triazinanes via a Formal (3 + 3) Annulation Reaction
摘要:
The synthesis of 3,4-dihydro-2H-1,3-thiazines from alpha-enolic dithioesters and 1,3,5-triazinanes has been achieved via a formal (3 + 3) annulation reaction under thermal conditions, where 1,3,5-triazinanes were utilized as three-atom synthons. This transformation is catalyst-free and additive-free.
Access to Imidazolidines via 1,3-Dipolar Cycloadditions of 1,3,5-Triazinanes with Aziridines
作者:Liang Tu、Zhenghui Li、Tao Feng、Shuyan Yu、Rong Huang、Jing Li、Wenxuan Wang、Yongsheng Zheng、Jikai Liu
DOI:10.1021/acs.joc.9b01959
日期:2019.9.6
The unprecedented 1,3-dipolar cycloaddition of 1,3,5-triazinanes and aziridines has been described. With readily available starting material, this method offers efficient access to a wide range of functionalized imidazolidine derivatives in moderate to good yields (up to 92%) under mild conditions. Preliminary mechanistic investigations show that the ring opened zwitterionic pathway product dominated
Synthesis of 1,2,3,4‐Tetrahydrobenzofuro[3,2‐
<i>d</i>
]pyrimidines via [4+2] Annulation Reaction of 1,3,5‐Triazinanes and Aurone‐Derived α,β‐Unsaturated Imines
A [4+2] annulation reaction of 1,3,5‐triazinanes and aurone‐derived α,β‐unsaturated imines has been developed, which enables the synthesis of 1,2,3,4‐tetrahydrobenzofuro[3,2‐d]pyrimidines under thermal conditions in high yields. This protocol is catalyst‐free and additive‐free.
A chiral Lewis acid-catalyzed enantioselective formal [2 + 2 + 2] cycloaddition of 1,3,5-triazinanes with azlactones or β,γ-unsaturated pyrazole amides was developed to synthesize chiral tertiary/quaternary tetrahydropyrimidin-4-one derivatives with good yields and enantioselectivities. Two competitive reaction pathways were proposed based on experiments.
The synthesis of hydrobenzoimidazoles frompara‐quinamines and 1,3,5‐triazinanes was achieved via a formal [3+2] annulation reaction in the presence of In(OTf)3 as the catalyst. Further studies demonstrated that the synthesis of hydrobenzooxazoles could also be accomplished via the same strategy frompara‐quinols and 1,3,5‐triazinanes.
[3 + 2]-Cycloaddition of Azaoxyallyl Cations with Hexahydro-1,3,5-triazines: Access to 4-Imidazolidinones
作者:Danqing Ji、Jiangtao Sun
DOI:10.1021/acs.orglett.8b00951
日期:2018.5.4
A novel base-promoted [3 + 2] cycloaddition reaction of azaoxyallyl cations with hexahydro-1,3,5-triazines has been developed, affording 4-imidazolidinones in moderate to good yields under mild reaction conditions. This simple but efficient protocol features cycloaddition of two in situ formed reactive species in the absence of a transition-metal catalyst.