@article { ISI:000249394900019, title = {Efficient synthesis of azetidine-2,3-diones from L-(+)-diethyl tartrate}, journal = {Synlett}, number = {14}, year = {2007}, month = {SEP}, pages = {2242-2246}, publisher = {GEORG THIEME VERLAG KG}, type = {Article}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A convenient route to enantiopure azetidine-2,3-diones is described. The chiral ketene generated from commercially available L-(+)-diethyl tartrate on Staudinger cycloaddition with different imines gave spiro-beta-lactams in good yields. These spiro-beta-lactams were transformed into azetidine-2,3-diones in excellent yields in a two-step process.

}, keywords = {Cycloaddition, imines, lactams, spiro compounds, stereoselective synthesis}, issn = {0936-5214}, doi = {10.1055/s-2007-985563}, author = {Chincholkar, Pinak M. and Puranik, Vedavati G. and Deshmukh, Abdul Rakeeb A. S.} } @article { ISI:000328335000013, title = {Simple synthesis of the novel antihistaminic drug olopatadine hydrochloride}, journal = {Synthesis-Stuttgart}, volume = {45}, number = {24}, year = {2013}, month = {DEC}, pages = {3399-3403}, publisher = {GEORG THIEME VERLAG KG}, address = {RUDIGERSTR 14, D-70469 STUTTGART, GERMANY}, abstract = {

A new alternative route for the synthesis of olopatadine is described. The present strategy involves a Lewis acid mediated ring opening of a cyclic ether to introduce 3-(dimethylamino)propylidene group as the side chain.

}, keywords = {antihistaminic drugs, chelates, Lewis acids, spiro compounds, zinc}, issn = {0039-7881}, doi = {10.1055/s-0033-1340008}, author = {Chavan, Subhash P. and Lasonkar, Pradeep B.} } @article { ISI:000368065300033, title = {Enantioselective synthesis of spirocyclohexadienones by NHC-catalyzed formal [3+3] annulation reaction of enals}, journal = {Angewandte Chemie-International Edition}, volume = {55}, number = {1}, year = {2016}, month = {JAN}, pages = {268-272}, publisher = {WILEY-V C H VERLAG GMBH}, address = {POSTFACH 101161, 69451 WEINHEIM, GERMANY}, abstract = {

The enantioselective synthesis of pyrazolone-fused spirocyclohexadienones was demonstrated by the reaction of alpha,beta-unsaturated aldehydes with alpha-arylidene pyrazolinones under oxidative N-heterocyclic carbene (NHC) catalysis. This atom-economic and formal [3+3] annulation reaction proceeds through a vinylogous Michael addition/spiroannulation/dehydrogenation cascade to afford spirocyclic compounds with an all-carbon quaternary stereocenter in moderate to good yields and excellent ee values. Key to the success of the reaction is the cooperative NHC-catalyzed generation of chiral alpha,beta-unsaturated acyl azoliums from enals, and base-mediated tandem generation of dienolate/enolate intermediates from pyrazolinones.

}, keywords = {annulation reactions, asymmetric catalysis, N-heterocyclic carbenes, organocatalysis, spiro compounds}, issn = {1433-7851}, doi = {10.1002/anie.201507802}, author = {Yetra, Santhivardhana Reddy and Mondal, Santigopal and Mukherjee, Subrata and Gonnade, Rajesh G. and Biju, Akkattu T.} } @article {45733, title = {Unified approach to fused and spirocyclic oxindoles through lewis-acid-promoted opening of spiroepoxyoxindoles with allylsilanes: application to the formal synthesis of (+/-)-physovenine}, journal = {European Journal of Organic Chemistry}, year = {2017}, month = {MAY }, pages = {2603-2609}, type = {Article}, abstract = {

A protocol for the construction of oxindoles containing all-carbon quaternary centres in a highly regioselective manner has been developed. The reaction involves opening of spiroepoxyoxindoles with allylsilanes to give Hosomi-Sakurai-type products as well as new silicon-containing spirocyclic oxindoles. A formal synthesis of (+/-)-physovenine was accomplished in five steps using this protocol.

}, keywords = {alkaloids, Allylation, annulation, Lewis acids, spiro compounds}, issn = {1434-193X}, doi = {10.1002/ejoc.201700259}, author = {Sharma, Brijesh M. and Yadav, Mahesh and Gonnade, Rajesh G. and Kumar, Pradeep} }