196314-29-1

Upstream product

• 24424-99-5 di-tert-butyl dicarbonate 
• 119240-64-1 (1'R,2'S,5'R)-2'-(2''-phenylpropan-2''-yl)-5'-methylcyclohexyl (E)-3-phenylpropenoate 
• 18107-18-1 diazomethyl-trimethyl-silane 

Downstream Products

• 224571-77-1 (-)-(4S,5S)-1-tert-butoxycarbonyl-4,5-dihydro-3-hydroxymethyl-4-phenyl-5-trimethylsilyl-1H-pyrazole 
• 224571-89-5 (-)-(4S,5S)-1-tert-butoxycarbonyl-3-tert-butyldimethylsilyloxymethyl-4,5-dihydro-4-phenyl-5-trimethylsilyl-1H-pyrazole 
• 224572-01-4 (+)-(3S,4R,5S)-1-tert-butoxycarbonyl-3-tert-butyldimethylsilyloxymethyl-4-phenyl-5-trimethylsilylpyrazolidine 
• 224572-35-4 (-)-(3S,4R,5S)-1-<(tert-butoxycarbonyl)amino>-3-(tert-butyldimethylsilyloxymethyl)-2-(ethoxycarbonyl)-4-phenyl-5-trimethylsilylpyrazolidine 
• 224572-18-3 (-)-(3S,4R,5S)-1-benzyloxycarbonyl-2-(tert-butoxycarbonyl)-5-tert-butyldimethylsilyloxymethyl-4-phenyl-3-trimethylsilylpyrazolidine 

Relevant academic research and scientific papers

First highly regio- and diastereoselective [3+2] cycloaddition of chiral nonracemic alkenyl Fischer carbene complexes with diazomethane derivatives: Preparation and synthetic applications of enantiomerically pure Δ2-pyrazolines

The [3+2] cycloaddition of alkenyl Fischer carbene complexes 1 and 6 with diazomethane derivatives to give Δ2-pyrazoline carbenes 2, 4, and 7 is described. The conversion of (-)-8-phenylmenthol-derived carbenes 6 into pyrazoline esters 9 through a one-pot cycloaddition-protection-oxidation is presented as an expeditious route to enantiomerically pure 3-alkoxycarbonyl-Δ2-pyrazolines in good yields and in a highly regio- and diastereoselective manner. Pyrazolidines 13 were synthesized in excellent overall yields from 9 through pyrazolines 11 and 12, the diastereoselective reduction of C=N bond being the key step. Azaprolines 16 and 17 were prepared in very good yields from epimeric trans-13 or cis-13 by oxidative deprotection of the silylated hydroxy group. In an alternative reaction, the pyrazolidine ring of 13 was reduced to obtain protected open-chain 2,4-diamino alcohols 19 with three chiral centers.

First diastereoselective [3+2] cycloaddition of chiral non-racemic alkenyl Fischer carbene complexes with diazomethane derivatives

(-)-8-Phenylmenthol derived pentacarbonylalkenyl(alkoxy)chromium carbene complexes react with diazomethane derivatives to give only one diastereomer of enantiomerically pure 4,5-dihydro-1H-pyrazoles; the one-pot synthesis of the corresponding esters is also described.