Mixed dialkylaluminum chlorides and mixed trimethylorganoaluminates in chemoselective 1,4 addition reactions to alkylidene malonic acid diethyl ester

Mixed alkyl-methyl- and aryl-methylorganoaluminum chlorides 6 were formed b y reaction of methylaluminum dichloride with organolithium or Grignard comp ounds and used for chemoselective 1,4 addition of higher alkyl, aryl, alken yl and alkinyl groups to alkylidine malonic esters 1 and 2. As an alternati ve, mixed trimethylorganoaluminates 7 can also be applied for these Michael addition reactions. For conjugate addition of alkenyl groups to alkylidene malonates and 2, alkenyl diisopropylalanes 10 obtained from alkynes and di isopropylaluminum hydride proved the most efficient reagents. Using these n ovel mixed organoaluminum compounds, P-branched malonic (carboxylic) acid d erivatives 3c, 8, 9 and 11 were obtained in good yields. The method offers a general access to beta-branched carboxylic derivatives of quite diverse s tructure not dependent on the commercial availability of the organoluminum chlorides.