Substrate-controlled crotylborationt from N-(tert-butoxycarbonyl)amino aldehydes
Abstract
Chiral or achiral (Z)-crotylorganoboron compounds add preferentially anti to N-(tert-butoxycarbonyl)amino aldehydes. N-(tert-Butoxycarbonyl)prolinal 3 presents a remarkably high diastereofacial selectivity. Double stereodifferentiation, starting from compound 3, allows complete diastereoselective access to the γ-amino-β-hydroxy-α-methyl acid dolaproine 1 present in the antiproliferative dolastatin 10.