1.
Chem Pharm Bull (Tokyo)
; 60(1): 21-2, 2012.
Artigo
em Inglês
| MEDLINE
| ID: mdl-22223370
RESUMO
A catalytic amount of tin(IV) chloride catalyzed formal [4+2] cycloaddition reaction of di-tert-butyl 2-ethoxycyclobutane-1,1-carboxylate with ketones or aldehydes to give diethyl 6-ethoxydihydro-2H-pyran-3,3(4H)-dicarboxylates, whereas two equivalents of trimethylsilyl triflate promoted tandem [4+2] cycloaddition and lactonization to afford 3-oxo-2,6-dioxabicyclo[2.2.2]octane-4-carboxylate esters.
Assuntos
Aldeídos/química , Ácidos Dicarboxílicos/química , Cetonas/química , Catálise , Ciclização , Ácidos Dicarboxílicos/síntese química , Lactonas/química , Compostos de Estanho/química
2.
Org Lett
; 12(14): 3266-8, 2010 Jul 16.
Artigo
em Inglês
| MEDLINE
| ID: mdl-20568828
RESUMO
N-p-Toluenesulfonyl (Ts) aldimines reacted with 3-ethoxycyclobutanones by catalysis of titanium(IV) chloride to afford 2,3-di- or 2,3,3-trisubstituted N-Ts-2,3-dihydro-4-pyridones. Synthesis of (+/-)-bremazocine was efficiently accomplished by using this method.