New allyl silane derivs. - are intermediates for 3-oxa-carbacycline derivs., esp. with E configuration

摘要

Allylsilane derivs. (I) are new. R1, R2 = a bond or R1 + R2 = R9-CH (R9 = 1-10C alkyl); R3, R4 = H, 1-10C alkyl, 5-7C cycloalkyl. 1-6C alkoxy, 6-10C aryl, 7-12C aralkyl, or when R1 + R2 form a bond, substd. propylene; R5 = H or alkyl, alkenyl or alkynyl with up to 20C opt. substd. by NH2, protected NH2, CH3NH, OH, COOH, SH or hal and opt. interrupted by O, S, NH or N(CH3); R6-R8 = 1-4C alkyl, 1-4C alkoxy or phenyl. Organozinc cpds. Zn(CH2SiR6R7R17)2 (IIIa) are also claimed. R17 = 1-4C alkoxy. Prepn. of (I) comprises reacting a cpd. of formula (II) with Zn(CH2SiR6R7R8)2 (III) where R15 = 1-4C alkyl or p-toluenesulphonyl. Free OH gps. in (II) are opt. protected and the reaction is carried out in the presence of NiCl2. (C6H5)2P(CH2)3P(C6H5)2 (=NiCl2dppp) as catalyst and with the addn. of a Li, Mg, or Zn salt. USE/ADVANTAGE - Cpds. (I) are intermediates for biologically active 3-oxa-carbacycline derivs. They are obtd. with high stereoselectivity in an E/Z ratio of 90:10 to 100:0 and are more suitable as intermediates than cpds. obtd. by EP 303562.