- A containing halogen light active 2 - oxo - 1, 3 - oxazine compounds and its preparation method and application
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The invention discloses a 2-carbonyl-1,3-oxazine compound and a preparation method therefor and application thereof. The structural formula of the 2-carbonyl-1,3-oxazine compound is shown in a formula II. The preparation method comprises: carrying out a reaction on a compound shown in a formula I and N-bromoacetamide (or 1,3-dibromo-5,5-dimethyl hydantoin) under the action of a scandium trifluoromethanesulfonate/monophosphine ligand. The photoactive 2-carbonyl-1,3-oxazine compound provided by the invention can be used for conveniently obtaining compounds containing 1,3-hydroxylamine structures and functionalized heterocyclic compounds through further conversion reactions, and meanwhile, a bromine atom can be introduced into the reaction. The functional groups can be further converted. Other functional groups are introduced, so that the compound has huge application value. According to the method provided by the invention, raw materials are easily synthesized, the reaction condition is mild, the operation is simple and convenient, the region selectivity is high, the enantioselectivty can reach up to over 99%, and the output reaches up to 72%. The formulae are shown in the description.
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Paragraph 0106-0109
(2017/08/23)
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- Enantioselective intramolecular cyclopropanations of allylic and homoallylic diazoacetates and diazoacetamides using chiral dirhodium(II) carboxamide catalysts
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Diazo decomposition of allylic and homoallylic diazoacetates 10a-p and 22a-j catalyzed by chiral dirhodium(II) tetrakis[methyl 2-pyrrolidone-5(S)-carboxylate], Rh2(SS-MEPY)4 (7), and its enantiomer, Rh2(5R-MEPY)4 (8), produces the corresponding intramolecular cyclopropanation products 11a-p and 23a-j in good to excellent yields and with exceptional enantioselectivity. Higher enantiocontrol is observed with allylic diazoacetates than with their homoallylic counterparts, but allylic diazoacetates are subject to greater variations in enantioselectivities with changes in substitution patterns on the carbon-carbon double bond. For example, the enantioselectivities in the intramolecular cyclopropanations of 3-alkyl/aryl-2(Z)-alken-1-yl diazoacetates are generally ≥94%, whereas the cyclizations of the homologous 4-alkyl/aryl-3(Z)-alken-1-yl diazoacetates are typically in the range of 70-90% ee. The corresponding 3-alkyl/aryl-2(E)-alken-1-yl and 4-alkyl/aryl-3(E)-alken-1-yl diazoacetates undergo cyclization with slightly lower ee's (54-85%). Although the Rh2(5S-MEPY)4-catalyzed cyclization of the 2-methallyl diazoacetate 10c proceeds with only 7% ee, alternative chiral dirhodium(II) catalysts, including those with methyl N-acylimidazolidin-2-one-4(5)-carboxylate ligands such as Rh2(4S-MACIM)4 (14) and Rh2(4S-MPAIM)4 (15), may be employed to increase the level of enantiocontrol to 78 and 65%, respectively. Some allylic diazoacetamides also undergo highly enantioselective cyclization to form cyclopropyl lactams as illustrated by the diazo decomposition of N-allyl diazoacetamide (19) in the presence of dirhodium(II) tetrakis[methyl 2-oxazolidinone-4(S)-carboxylate], Rh2(4S-MEOX)4, to give the 3-azabicyclo[3.1.0]hexan-2-one 20 in 98% ee. The absolute configuration and the level of enantiocontrol in these intramolecular cyclopropanations have been interpreted by a transition state model in which the important determinants are (i) the preferred conformation about the rhodium-carbon bond; (ii) the trajectory of approach of the double bond to the metallocarbene center; and (iii) the orientation of the double bond with respect to the chiral face of the catalyst.
- Doyle, Michael P.,Austin, Richard E.,Bailey, A. Scott,Dwyer, Michael P.,Dyatkin, Alexey B.,Kalinin, Alexey V.,Kwan, Michelle M. Y.,Liras, Spiros,Oalmann, Christopher J.,Pieters, Roland J.,Protopopova, Marina N.,Raab, Conrad E.,Roos, Gregory H. P.,Zhou, Qi-Lin,Martin, Stephen F.
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p. 5763 - 5775
(2007/10/02)
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