Facile chemo-, regio-, and diastereoselective approach to cis-3,5-disubstituted gamma-butyrolactones and fused gamma-butyrolactones.
Chemoselective SN2' condensation of primary enolates of alkyl methyl ketones 2a-e with dimethyl bromomethylfumarate (1) followed by highly diastereoselective NaBH4 reduction of the ketone function in the formed ketodiesters 3a-e and the regioselective in situ lactonization of the unisolable intermediates 4a-e exclusively furnished the cis-3,5-disubstituted gamma-butyrolactones (+/-)-5a-e in very good yields. Similarly, the face-selective coupling reaction of cyclohexanone enolate with 1 to form a mixture of diastereomers in an 8:2 ratio followed by a highly selective reductive cyclization of 9 plus 10 exclusively provided the cis-octahydrobenzofuran (+/-)-12 in 70% overall yield.
Baag
Md Merajuddin
MM
Division of Organic Chemistry (Synthesis) and Centre for Material Characterization, National Chemical Laboratory, Pune 411 008, India.
Puranik
Vedavati G
VG
Argade
Narshinha P
NP
D015107:4-Butyrolactone / Q000031:analogs & derivatives / Q000138:chemical synthesis*; D001572:Benzofurans / Q000737:chemistry; D003512:Cyclohexanones / Q000737:chemistry; D004952:Esters / Q000737:chemistry; D007659:Ketones / Q000737:chemistry; D018020:Lithium Compounds / Q000737:chemistry; D008968:Molecular Conformation; D013237:Stereoisomerism
D001572:Benzofurans; D003512:Cyclohexanones; D004952:Esters; D007659:Ketones; D018020:Lithium Compounds; C036468:cyclohexanone; D015107:4-Butyrolactone