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1.
Chem Pharm Bull (Tokyo) ; 65(11): 997-999, 2017.
Article in English | MEDLINE | ID: mdl-29093299

ABSTRACT

An enantioselective intermolecular Rauhut-Currier (RC) reaction of nitroalkenes with ethyl allenoate has been established with quinidine-derived ß-isocupreidine. The present RC reaction afforded α-functionalized allenoates 3 in up to 94% yield with 59% enantiomeric excess (ee).


Subject(s)
Alkadienes/chemistry , Alkenes/chemistry , Esters/chemistry , Nitro Compounds/chemistry , Catalysis , Cyclization , Molecular Structure , Stereoisomerism
2.
Org Lett ; 19(19): 5426-5429, 2017 10 06.
Article in English | MEDLINE | ID: mdl-28956612

ABSTRACT

The first enantio- and diastereoselective Betti/intramolecular aza-Michael sequence carried out using a C3-symmetric chiral trisimidazoline organocatalyst is reported. The reaction of phenols and N-tosylimines bearing a Michael acceptor moiety afforded densely functionalized 1,3-disubstituted isoindolines bearing two stereogenic centers as single diastereomers in high yields (≤93%) and excellent enantioselectivities (≤99.9%).

3.
Chem Commun (Camb) ; 53(55): 7724-7727, 2017 Jul 06.
Article in English | MEDLINE | ID: mdl-28589974

ABSTRACT

Mixing of acryloylchloride, dienone 2, N,N-diisopropylethylamine with chiral organocatalyst 5a, which could simultaneously act as Brønsted and Lewis base catalysts, led to a one-pot amidation/Rauhut-Currier sequence, affording α-methylidene-γ-lactams 4. Catalyst 5a could be recovered and reused by acid/base extraction without any loss of catalytic activity in the stepwise protocol.

4.
Org Biomol Chem ; 14(2): 761-767, 2016 Jan 14.
Article in English | MEDLINE | ID: mdl-26587584

ABSTRACT

C3-Symmetric chiral trisimidazolines with m-chloroperbenzoic acid promoted the organocatalytic oxidation of N-sulfonyl ketimine. The present imidazoline catalysis produced oxaziridines bearing a tetrasubstituted carbon stereogenic center in high yields with up to 87% ee.

5.
Angew Chem Int Ed Engl ; 54(51): 15511-5, 2015 Dec 14.
Article in English | MEDLINE | ID: mdl-26537173

ABSTRACT

An enantio-, diastereo-, regio-, and chemoselective phosphine-catalyzed ß,γ-umpolung domino reaction of allenic esters with dienones has been developed for the first time. The designed sequence, involving oxy-Michael and Rauhut-Currier reactions, produced highly functionalized tetrahydrobenzofuranones, bearing a chiral tetrasubstituted stereogenic center, in up to 96 % ee.

6.
Org Biomol Chem ; 13(34): 9022-8, 2015 Sep 14.
Article in English | MEDLINE | ID: mdl-26214279

ABSTRACT

A highly enantioselective aza-Morita-Baylis-Hillman (aza-MBH) reaction of isatin-derived ketimines with acrolein was established using ß-isocupreidine (ß-ICD) or α-isocupreine (α-ICPN) as a chiral acid-base organocatalyst. The present protocol readily furnished (S) or (R)-aza-MBH adducts with a chiral tetrasubstituted carbon stereogenic center in up to 98% ee.


Subject(s)
Acrolein/chemistry , Hydroxyquinolines/chemistry , Imines/chemistry , Isatin/chemistry , Nitriles/chemistry , Quinuclidines/chemistry , Catalysis , Molecular Structure , Stereoisomerism
7.
Org Lett ; 16(16): 4162-5, 2014 Aug 15.
Article in English | MEDLINE | ID: mdl-25089369

ABSTRACT

Highly E-selective all-carbon tetrasubstituted alkenes with a C(sp(3))-F unit have been synthesized through a dehydroxyfluorination of Morita-Baylis-Hillman (MBH) adducts which can be readily prepared from α,ß-unsaturated carbonyl compounds and α-keto esters. A variety of subsequent transformations afforded monofluoromethyl substituted heterocycles in high yields.

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