166272-46-4

Upstream product

• 80522-42-5 triisopropylsilyl trifluoromethanesulfonate 
• 162892-00-4 Benzo[1,2-b;4,3-b']dithiophen-2-yl-methanol 

Relevant academic research and scientific papers

Synthesis, enzymic resolution and enantiomeric enhancement of bis(hydroxymethyl)[7]thiaheterohelicenes

Racemic bis(hydroxymethyl)[7]thiaheterohelicene 9 has been prepared in eight steps (33% overall yield) from 2-(hydroxymethyl)benzo[1,2-b:4,3-b′]dithiophene 1. Lipase (Pseudomonas cepacia)-catalyzed transesterification of diol 9 by vinyl acetate in dichloromethane produces optically stable (P)-bis(hydroxymethyl)[7]thiaheterohelicene [(P)-9] with 98% ee along with the corresponding monoacetate [(M)-10] and the diacetate [(M)-11]. Hydrolysis of acetates (M)-10 and (M)-11 by aq. NaOH gives (M)-9 in 77% and 94% ee, respectively. In contrast, the enzymic resolution of diol 9 with Candida antarctica afforded diol (M)-9 in 92% ee. Column chromatography of optically enriched helicenediol 9 on silica gel shows an enantiomeric enhancement. A possible cause of the phenomenon is discussed.

Enantioselective synthesis of helical molecules: Lipase-catalyzed resolution of bis(hydroxymethyl)[7]thiaheterohelicene

Lipase (Pseudomonas cepacia)-catalyzed transesterification of racemic 2, 13-bis(hydroxymethyl)dithieno[3,2-e:3′,2′-e′]benzo[1,2-b:4,3- b′]bis[1]benzothiophene by vinyl acetate in dichloromethane proceeded with a high degree of enantioselectivity to give (P)-(+)-bis(hydroxymethyl)[7]thiaheterohelicene (45% yield, 98% ee), and the corresponding monoacetate (37% yield) and diacetate (13% yield). Reduction of the monoester by LiAlH4 gave (M)-(-)-bis(hydroxymethyl)[7]thiaheterohelicene with 80% ee and the diester gave the same enantiomer with.