591218-65-4Relevant academic research and scientific papers
Synthesis of Alkynyl-Glycinols by Lewis Acid Catalyzed Propargylic Substitution of Bis-Imidates
Sirotkina, Jekaterina,Grigorjeva, Liene,Jirgensons, Aigars
, p. 6900 - 6908 (2015)
Racemic and enantioenriched alkynyl-glycinols can be synthesized by Lewis acid catalyzed cyclization reaction of bis-trichloracetimidates derived from alkynyl-glycols. The cyclization proceeds selectively to give 4-alkynyl-oxazolines as the propargylic substitution products. Enantioenriched bis-imidates that contain an alkyl or trimethylsilyl substituent at the acetylene gave oxazolines with complete inversion of configuration. In turn, considerable racemization was observed in the cyclization of bis-imidates that contain a phenyl substituent. The racemization for these substrates can be suppressed by introduction of the electronegative substituent at the phenyl ring. Oxazolines prepared by bis-imidate cyclization reaction can be readily transformed to protected alkynyl-glycol derivatives. Racemic and enantioenriched alkynyl-glycinol derivatives can be synthesized by Lewis acid catalyzed cyclization reaction of bis-trichloroacetimidates into oxazolines.
Utilization of whole cell mediated deracemization in a chemoenzymatic synthesis of enantiomerically enriched polycyclic chromeno[4,3-b] pyrrolidines
Saravanan, Thangavelu,Jana, Sushital,Chadha, Anju
, p. 4682 - 4690 (2014/06/24)
Various aryl and alkyl substituted optically pure propargyl alcohols were obtained with excellent ee (up to >99%) and isolated yields (up to 87%) by deracemization using whole cells of Candida parapsilosis ATCC 7330. The whole cells show substrate specificity towards alkyl substituted propargyl alcohols and a switch in the enantioselectivity has been observed from 'R' to 'S' upon increasing the chain length. For the first time, enantiopure (R)-4-(3-hydroxybut-1-ynyl)benzonitrile, (R)-4-(biphenyl-4-yl)but-3-yn-2-ol, (S)-ethyl 3-hydroxy-5-phenylpent-4-ynoate and (S)-4-phenylbut-3-yne-1,2-diol were obtained using this strategy. Optically pure propargyl alcohol thus obtained was used as a chiral starting material in the synthesis of enantiomerically enriched poly-substituted pyrrolidines and a pyrrole derivative successfully demonstrating a chemoenzymatic route. This journal is
