@article { ISI:000303157400022, title = {Synthesis and structural characterization of homochiral homo-oligomers of cis-gamma-methoxy-substituted cis- and trans-furanoid-beta-amino acids}, journal = {European Journal of Organic Chemistry}, number = {13}, year = {2012}, month = {MAY}, pages = {2656-2663}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

Herein we describe the synthesis of cis-/trans-3-aminotetrahydrofuran-2-carboxylic acids (cis-/trans-FAA) having a ?-methoxy group cis to the amine. The homo-oligomers of these two diastereomeric FAAs have been prepared. Preliminary investigation of their solution secondary structures revealed that they are the same as the homo-oligomers of the parent cis-/trans-FAA with the methoxy group only being a spectator substituent.

}, keywords = {Amino acids, helical structures, Oxygen heterocycles, Peptides}, issn = {1434-193X}, doi = {10.1002/ejoc.201101424}, author = {Giri, Awadut G. and Jogdand, Ganesh F. and Rajamohanan, Pattuparampil R. and Pandey, Sunil K. and Ramana, Chepuri V.} } @article { ISI:000346161500008, title = {Protecting-group-free diastereoselective total synthesis of (+/-)-6-epi-cleistenolide and chemoenzymatic synthesis of (-)-6-epi-cleistenolide}, journal = {European Journal of Organic Chemistry}, number = {36}, year = {2014}, month = {DEC}, pages = {8049-8054}, publisher = {WILEY-V C H VERLAG GMBH}, address = {BOSCHSTRASSE 12, D-69469 WEINHEIM, GERMANY}, abstract = {

A short, efficient, practical, and protecting-group-free diastereoselective total synthesis of (+/-)-6-epi-cleistenolide (1) has been achieved in five steps in 60\% overall yield. The use of a chemoenzymatic approach also gave (-)-6-epi-cleistenolide (1) (\>99.9\% ee). The Achmatowicz reaction, chemoselective oxidation of a hemiacetal, diastereoselective 1,3-anti reduction of alpha-hydroxy ketone, and enzymatic resolution of a 1,3-diol are the key features of this linear total synthesis. The synthetic strategy demonstrated in this paper could be extended for an asymmetric total synthesis of (-)-cleistenolide (1) and related biologically active natural products.

}, keywords = {Asymmetric synthesis, diastereoselectivity, Enzyme catalysis, Lipases, Oxygen heterocycles, Total synthesis}, issn = {1434-193X}, doi = {10.1002/ejoc.201403123}, author = {Mahajan, Pankaj S. and Gonnade, Rajesh G. and Mhaske, Santosh B.} } @article {48027, title = {Divergent annulation of spiro[indoline-pyran] and fused (Epoxyetheno)indeno-furan from 1,2-diketone and 1-cyanoketone}, journal = {European Journal of Organic Chemistry}, volume = {2022}, year = {2022}, month = {AUG}, pages = {e202101534}, type = {Article}, abstract = {

A simple and efficient method for the construction of spiro[indoline-pyran] and fused (epoxyetheno)indeno[1,2-b]furan compounds from 1-cyanoketones and 1,2-diketone has been developed. The synthesis proceeded via the Knoevenagel and Michael adduct through intramolecular/Paal-Knorr cyclization under similar reaction condition. The less commonly used 1-cyanoketones and active carbonyl compounds served as the indole containing pyran and bicyclic furan source for the preparation of a new series of heterocyclic compounds. This heterocyclic structure allows one and more than one tetra-substituted carbon center and sequential hexa- and penta-cyclic core under very mild conditions and shows excellent chemo and regioselectivity. In addition, the synthesis of spiro[indoline-pyran] and (epoxyetheno)indeno[1,2-b]furan was demonstrated in a gram scale.

}, keywords = {Diverse synthesis, Intramolecular, Knoevenagel and Michael adduct, molecular diversity, Oxygen heterocycles, Paal-Knorr cyclization}, issn = {1434-193X}, doi = {10.1002/ejoc.202101534}, author = {Yadav, Maruti B. and Vagh, Sandip S. and Jeong, Yeon Tae} }