950902-11-1Relevant academic research and scientific papers
Practical enzymatic desymmetrization of 2-(ethoxycarbonyl)propane-1,3-diyl dihexanoate and model cyclization for the A-D ring system of lysergic acid
Miyata, Sachiho,Kumamoto, Takuya,Ishikawa, Tsutomu
, p. 1420 - 1438 (2008/02/08)
Porcine pancreas lipase-catalyzed hydrolysis of symmetrical 2-(ethoxycarbonyl)propane-1,3-diyl dihexanoate, under the modified conditions of the Seebach protocol, afforded a desymmetrized monohexanoate in 40-51% yield with 91-94% ee, even in a gram-scale reaction. The absolute configuration of a half-hydrolyzed (-)-product was determined to be (R) by conversion to a known 2-methylpropane-1,3-diol derivative. Samarium iodide-induced radical cyclization of 2-oxo-3-phenylethylamine with a C4 unit on the N-atom, derived from the racemic monohexanoate, afforded a 3-phenylpiperidine derivative as a model construction of the A-D ring system of lysergic acid.
Chemoenzymatic Preparation of Asymmetrized Tris(hydroxymethyl)methane (THYM*) and of Asymmetrized Bis(hydroxymethyl)acetaldehyde (BHYMA*) as New Highly Versatile Chiral Building Blocks
Guanti, Giuseppe,Banfi, Luca,Narisano, Enrica
, p. 1540 - 1554 (2007/10/02)
A series of asymmetrized tris(hydroxymethyl)methanes 2 and bis(hydroxymethyl)acetaldehydes 3 have been prepared in both enantiomeric forms through a chemoenzymatic methodology.The key step is the highly enantioselective PPL-catalyzed monohydrolysis of 2(E)-alkenyl-1,3-diacetoxypropanes 25-27.A careful study on the effect of unsaturations adjacent to the prochiral center in a series of 2-substituted 1,3-diacetoxypropanes has confirmed the suggested beneficial effect of a ? system in that position but has also unveiled an unprecedented dramatic effect of double-bond configuration on enantioselectivity.A new empirical model for the interpretation of these and other results, based both on polarity and steric arguments, is proposed.This study provides a general protocol for the efficient synthesis of asymmetrized 1,3-propanediols bearing in position 2 saturated or unsaturated carbon chains.
