Question

1a) For flat sm A, draw its low energy conformation in the box. Draw all alpha Hs. b) Draw the product of hydride addition via axial attack and via equatorial attack as the chair product and the equivalent flat product. Label each flat product as anti/syn. equatorial attack A = chair product flat product t-Bu axial flat sm attack c) Which trajectory and product will be preferred when LiAlH4 is the reductant? Why? d) Which trajectory and product will be preferred with L-selectride and why?

Answer 1

TAHU M. lam) laxial attack Soln. Иа HO 4 +- Bu H t-bu t-Bu should be at equitorial position SYN with respect of Håb." for lower energy conformation t-Bu- Ante lehen with respect to ob Oy 7-8 +-Bu ti " н Solna na +-BU +-By H +- Bu Cis-product SYN +-Bu LiAlHY BU twindy +- BU +-Bu Small Beducing ни apent axial attack) Preferred +- BU 4 no-steric thinderance create with respect Product +-Bu to t-Bugp. Anti

L-selechide + Bu more bulky +-34 (preferred equiterial attack t-Bu oh +- B4 SYN +-Bugp. bulky & L-selecbride abo bulky (axial attack create steric hinderance) ( so preferred equitorial) (cis protect)