01429nas a2200169 4500008004100000022001400041245013600055210006900191260007100260300001400331490000700345520070500352100002601057700002601083700001901109856013101128 2007 eng d a0022-326300aFacile chemo-, regio-, and diastereoselective approach to cis-3,5-disubstituted gamma-butyrolactones and fused gamma-butyrolactones0 aFacile chemo regio and diastereoselective approach to cis35disub a1155 16TH ST, NW, WASHINGTON, DC 20036 USAbAMER CHEMICAL SOCcFEB a1009-10120 v723 a
Chemoselective S(N)2' 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.
1 aBaag, Md., Merajuddin1 aPuranik, Vedavati, G.1 aArgade, N., P. uhttp://library.ncl.res.in/content/facile-chemo-regio-and-diastereoselective-approach-cis-35-disubstituted-gamma-butyrolactones