Exploiting the Ring Strain in Bicyclo[2.2.1]heptane Systems for the Stereoselective Preparation of Highly Functionalized Cyclopentene, Dihydrofuran, Pyrroline, and Pyrrolidine Scaffolds
作者:Elena Moreno-Clavijo、Antonio J. Moreno-Vargas、Raphaëlle Kieffer、Thérèse Sigstam、Ana T. Carmona、Inmaculada Robina
DOI:10.1021/ol2027009
日期:2011.12.2
bridgehead substituted bicyclo[2.2.1]hept-2-enes giving rise to orthogonally functionalized cyclopentene, 2,5-dihydrofuran, and 3-pyrroline scaffolds. Retro-Dieckman reactions were easily carried out on 3-tosyl-(7-carba/7-oxa/7-aza)bicyclo[2.2.1]hept-5-en-2-ones. Retro-aldol reactions of N-Boc-3-tosyl-7-azabicyclo[2.2.1]hept-5-en-2-ol and functionalized N-Boc-3-tosyl-7-azabicyclo[2.2.1]heptan-2-ols yield
双环体系的高应变驱动桥头取代的双环[2.2.1]庚-2-烯上的逆向缩合反应,从而产生正交官能化的环戊烯,2,5-二氢呋喃和3-吡咯啉骨架。Retro-Dieckman反应很容易在3-tosyl-(7-carba / 7-oxa / 7-aza)双环[2.2.1] hept-5-en-2-ones上进行。的复古羟醛缩合反应Ñ -Boc-3-甲苯磺酰基-7-氮杂双环[2.2.1]庚-5-烯-2-醇和官能Ñ -Boc-3甲苯磺酰基-7-氮杂双环[2.2.1]庚烷2-ols立体选择性地产生官能化的吡咯烷支架。相同的反应不适用于相应的降冰片烯和7-氧杂降冰片烯衍生物。