Rhodium-Catalyzed C═N Bond Formation through a Rebound Hydrolysis Mechanism and Application in β-Lactam Synthesis
作者:Long Chen、Linxing Zhang、Ying Shao、Guangyang Xu、Xinhao Zhang、Shengbiao Tang、Jiangtao Sun
DOI:10.1021/acs.orglett.9b01312
日期:2019.6.7
this transformation proceeds via a novel rebound hydrolysis mechanism. Furthermore, a three-component reaction was explored to synthesize highly functionalized β-lactams in good yields and diastereoselectivities.
Asymmetric Synthesis of α-Allyl-α-Aryl α-Amino Acids by Tandem Alkylation/π-Allylation of α-Iminoesters
作者:John M. Curto、Joshua S. Dickstein、Simon Berritt、Marisa C. Kozlowski
DOI:10.1021/ol500506t
日期:2014.4.4
The first asymmetric synthesis of α-allyl-α-aryl α-amino acids by means of a three-componentcoupling of α-iminoesters, Grignard reagents, and cinnamyl acetate is reported. Notably, the enolate from the tandem process provides a much higher level of reactivity and selectivity than the same enolate generated via direct deprotonation, presumably due to differences in the solvation/aggregation state.
Chemo- and Enantioselective Brønsted Acid-Catalyzed Reduction of α-Imino Esters with Catecholborane
作者:Dieter Enders、Andreas Rembiak、Bianca Anne Stöckel
DOI:10.1002/adsc.201300352
日期:2013.7.8
The chemo‐ and enantioselectivereduction of α‐imino esters with catecholborane has been developed employing 10 mol% of an enantiopure BINOL‐based phosphoric acid as organocatalyst. Various differently substituted aromatic α‐amino acid derivatives can be achieved in almost quantitative yields and very good to excellent enantioselectivities of up to 96% ee under mild reaction conditions.
Catalytic Conversion of Diazocarbonyl Compounds to Imines: Applications to the Synthesis of Tetrahydropyrimidines and β-Lactams
作者:Michael D. Mandler、Phong M. Truong、Peter Y. Zavalij、Michael P. Doyle
DOI:10.1021/ol403427s
日期:2014.2.7
The synthesis of α-carbonylimines by rhodium(II)-catalyzed reactions of α-diazoesters and organic azides has been developed and applied in hetero-Diels–Alder reactions to form highly functionalized tetrahydropyrimidines and in a one-pot, multicomponent transformation between aryldiazoacetates, p-anisyl azide, and an enonediazoacetate to produce β-lactams in high yields and diastereoselectivities.
Novel metal-free, readily available chiral catalytic systems for the enantioselective reduction of keto imines are reported. Different β-imino esters were reduced by trichlorosilane in the presence of 10 mol% of a chiral Lewis base easily obtained in one step only from prolinol, in high yields and in up to 85% enantioselectivity; imines bearing an inexpensive and removable chiral auxiliary, were reduced with complete control of the absolute stereochemistry. The methodology was successfully extended to the stereoselective synthesis of α-amino esters.