Asymmetric synthesis of propargylic alcohols via aldol reaction of aldehydes with ynals promoted by prolinol ether–transition metal–Brønsted acid cooperative catalysis
作者:Enrique Gómez-Bengoa、Jesús M. García、Sandra Jiménez、Irati Lapuerta、Antonia Mielgo、José M. Odriozola、Itziar Otazo、Jesús Razkin、Iñaki Urruzuno、Silvia Vera、Mikel Oiarbide、Claudio Palomo
DOI:10.1039/c3sc51027a
日期:——
A catalytic and highly stereoselective entry to propargylic alcohols and products derived thereof is reported based on an unprecedented cross-aldol coupling between unmodified aldehydes and ynals. The method requires an amineâmetal saltâBrønsted acid ternary catalyst system and implies synergistic activation of the donor aldehyde via enamine and of the acceptor carbonyl via unique and reversible metalâalkyne complexation. Specifically, by using a combined α,α-dialkylprolinol silyl etherâCuIâPhCO2H catalyst system, remarkably high levels of diastereo- and enantioselectivity (anti/syn up to >20â:â1, ee up to >99%) are achieved.
报告基于未改性醛和炔之间前所未有的交叉醛偶联,报道了一种催化性和高度立体选择性的丙炔醇及其衍生产品。该方法需要胺-金属盐-勃氏酸三元催化剂体系,并意味着通过烯胺对供体醛进行协同活化,以及通过独特且可逆的金属-炔烃络合对受体羰基进行协同活化。具体来说,通过联合使用δ,δ-二烷基脯氨醇硅基醚âCuIâPhCO2H催化剂体系,可实现极高的非对映选择性和对映体选择性(反/同步可达>20â:â1,ee可达>99%)。