G. Niel et al., SUBSTRATE-CONTROLLED CROTYLBORATION FROM N-(TERT-BUTOXYCARBONYL)AMINOALDEHYDES, Journal of the Chemical Society. Perkin transactions. I, (10), 1994, pp. 1275-1280
Chiral or achiral (Z)-crotylorganoboron compounds add preferentially a
nti to N-(tert-butoxycarbonyl)-amino aldehydes. N-(tert-Butoxycarbonyl
)prolinal 3 presents a remarkably high diastereofacial selectivity. Do
uble stereodifferentiation, starting from compound 3, allows complete
diastereoselective access to the gamma-amino-beta-hydroxy-alpha-methyl
acid dolaproine 1 present in the antiproliferative dolastatin 10.