Cyclocondensation of b-Oxonitriles with Ketones or Aldehydes
摘要:
beta-Oxonitriles (1) are easily condensed with cyclic ketones (2a-e) in anhydrous strong acidic conditions to give 1-oxa-5-azaspiro[5.5]undec-2-en-4-ones (3a-e). In the same manner acyclic ketones (2f,g) or aldehydes (2h,i) afford 2,3-dihydro-4H-1,3-oxazin-4-ones (3f-i). The mechanism of this cyclocondensation is discussed.
2,3-Dihydro-4H-1,3-oxazin-4-ones, Novel Auxiliaries for the Stereoselective Synthesis of 1β-methylcarbapenems
作者:Do K. Pyun、Won J. Jeong、Hee J. Jung、Jae H. Kim、Jin S. Lee、Cheol H. Lee、Bong J. Kim
DOI:10.1055/s-2001-18778
日期:——
as efficient auxiliaries for the stereoselectivesynthesis of β-methylcarbapenem intermediate 2. Reformatsky-type reactions of 4-acetoxyazetidinone with α-bromopropionyl dihydrooxazinone 10 provided β-methylazetidinones 4 in high diastereoselectivities. The auxiliaries 9 were also easily removed in the Dieckmann cyclization leading to β-methylcarbapenem skeletons. Practical synthesis of β-methylenolphosphates
Rearrangement of 1-Oxa-5-azabicyclo[5.5]undec-2-en-4-ones to 5,6,7,8-Tetrahydroquinolin-2(1H)-ones
作者:J. F. Stambach、L. Jung、R. Hug
DOI:10.1055/s-1998-2039
日期:1998.3
Cyclocondensation of b-Oxonitriles with Ketones or Aldehydes
作者:Jean-Fran腔is Stambach、Louis Jung、Raymond Hug
DOI:10.3987/com-93-6536
日期:——
beta-Oxonitriles (1) are easily condensed with cyclic ketones (2a-e) in anhydrous strong acidic conditions to give 1-oxa-5-azaspiro[5.5]undec-2-en-4-ones (3a-e). In the same manner acyclic ketones (2f,g) or aldehydes (2h,i) afford 2,3-dihydro-4H-1,3-oxazin-4-ones (3f-i). The mechanism of this cyclocondensation is discussed.