Novel beta-lactams, novel preparation of taxanes and novel sidechain bearing taxane

PURPOSE: To produce novel β-lactams useful for an intermediate or the like in the preparation of a side chain-bearing taxanes valuable for a carcinostatic agent by hydrolyzing a 3-acetyloxy-azetidinone derivative and then, reacting an alkoxyalkenyl compound with the hydrolyzed derivative. CONSTITUTION: An optically active (3R-cis)-3-hydroxy-4-substituted-2-azetidinone of formula I (R 4 is an aryl group) is obtained by enzymatically hydrolyzing racemic 3-acetyloxy-4-substituted-2-azetidinone to produce (3R-cis)-3-acetyloxy-4- substituted-2-azetidinone and then, by hydrolyzing the latter using a base. Then, this compound is reacted with an alkoxyalkenyl compound of formula II (R 1a or R 2 is an alkyl or together form a cycloalkyl or the like; R 3 is an alkyl) in the presence of an acid catalyst to produce a compound of formula III (R 1 is the same as R 1a ) and then, if necessary, N-acylating to produce novel β-lactam of formula IV (R 5 is H, arylcarbonyl or the like). COPYRIGHT: (C)1994,JPO