Asymmetric hetero Diels–Alder reaction of Danishefsky's dienes and glyoxylates with chiral bis(oxazolinyl)phenylrhodium(III) aqua complexes, and its mechanistic studies
Asymmetric heteroDiels–Alderreaction of Danishefsky'sdienes with glyoxylates is catalyzed in high enantioselectivity and cis (endo)-diastereoselectivity by chiral (Phebox)RhCl2(H2O) complexes [Phebox=2,6-bis(oxazolinyl)phenyl], via the concerted [4+2] mechanism with perpendicular conformation of two carbonyl moieties of glyoxylates. Dibromide and difluoride complexes were newly synthesized and found
Asymmetric Hetero-Diels–Alder Reaction of Danishefsky’s Dienes with α-Carbonyl Esters Catalyzed by an Indium(III)–PyBox Complex
作者:Bei Zhao、Teck-Peng Loh
DOI:10.1021/ol400841s
日期:2013.6.21
An efficient catalytic enantioselective hetero-Diels–Alderreaction of Danishefsky’s dienes with α-carbonyl esters using a chiral In(III)–pybox complex has been demonstrated. This protocol offers several advantages, including mildreaction conditions, relatively low catalyst loading, and good to excellent enantioselectivities. Furthermore, the absolute configurations of the new alkynyl-containing products
Chiral bis-trifluoromethanesulfonylamide as a chiral Brønsted acid catalyst for the asymmetric hetero Diels–Alder reaction with Danishefsky’s diene
作者:Takayuki Tonoi、Koichi Mikami
DOI:10.1016/j.tetlet.2005.07.043
日期:2005.9
Bis-trifluoromethanesulfonylamide (bis-triflylamide) itself works as an efficient chiral Brønstedacidcatalyst for the hetero Diels–Alderreactions between Danishefsky’s diene and glyoxylate or phenylglyoxal presumably through double hydrogen bonding.
Importance of chiral activators in the asymmetric catalysis of Diels-Alder reactions by chiral titanium(IV) complexes
作者:Satoru Matsukawa、Koichi Mikami
DOI:10.1016/s0957-4166(97)00045-1
日期:1997.3
Asymmetric activation of chiraltitanium(IV) complexes is found to be essential to provide higher levels of enantioselectivity than that attained by enantiopure catalysts in Diels-Alder reactions of the Danishefsky diene and glyoxylate.
Commercially available (salen)Cr(III)Cl 4c and (salen)Co(II) 5a complexes were found to promote [4+2]cycloaddition of 1-methoxybuta-1,3-diene 1 to n-butyl glyoxylate 2, affording 6-substituted 2-methoxy-5,6-dihydro-2H-pyrans 3 in good yield and with enantioselectivites of 70-90% ee. The catalyst 5a was also effective in the reaction of Danishefsky's diene 6, piperylene 8 and 2,3-dimethylbuta-1,3-diene 10 with glyoxylate 2, however enantioselectivities were lower. (C) 2004 Elsevier Ltd. All rights reserved.