HYDROBORATION OF VINYLGLYCINE AND ALLYLGLYCINE AS A ROUTE TO BORON-DERIVATIVES OF ALPHA-AMINO-ACIDS

The hydroboration of protected vinylglycine and allylglycine with dicy clohexyl- or diisopinocampheylborane occurs chimio- and regioselective ly with attachment of boron to the less substituted end of the carbon- carbon double bond. Homoserine or delta-hydroxynorvaline are readily o btained by H2O2/CH3CO2Na oxidation of dicyclohexylborane derivatives a nd 2-amino-4-boronobutanoic acid or 2-amino-5-boronopentanoic acid by reaction of diisopinocampheylborane derivatives with excess of ethanal and deprotection. Copyright (C) 1996 Elsevier Science Ltd