Efficient Enantioselective Hetero-Diels−Alder Reaction of Brassard's Diene with Aliphatic Aldehydes: A One-Step Synthesis of (<i>R</i>)-(+)-Kavain and (<i>S</i>)-(+)-Dihydrokavain
作者:Lili Lin、Zhenling Chen、Xu Yang、Xiaohua Liu、Xiaoming Feng
DOI:10.1021/ol8002282
日期:2008.3.1
An efficient catalytic asymmetric hetero-Diels-Alder reaction of Brassard's diene with aliphatic aldehydes was reported. The catalyst, which was generated from (R)-BINOL, Ti(i-PrO)4, and 4-picolyl chloride hydrochloride, promoted the reaction smoothly to afford the corresponding alpha,beta-unsaturated delta-lactone derivatives in moderate-to-good yields (46-79%) with high enantioselectivities (up to
报道了Brassard's二烯与脂族醛的高效催化不对称杂Diels-Alder反应。由(R)-BINOL,Ti(i-PrO)4和4-picolyl chloride盐酸盐生成的催化剂可以平稳地促进反应,从而提供相应的α,β-不饱和δ-内酯衍生物。具有高对映选择性(高达88%ee)的良好收率(46-79%)。天然产物(R)-(+)-kavain(70%ee,单重结晶后ee> 99%ee)和(S)-(+)-二氢卡哇因(84%ee)也使用此方法一步制备。