Methods:A new approach to total synthesis of (-)-lasubine Ⅱ was established from readily available starting materials,via the new synthetic sequence including the creation of stereogenic centers through two sequential highly stereoselective Roush allylborations,SN2 cyclization and ring-closing metathesis reactions for the construction of the lasubine′s quinolizidine skeleton.

A new synthetic strategy employing 1,3-diene-ene ring-closing metathesis (RCM) is proposed for formation of the 16-membered macrolactone in this thesis work.

Ring closing metathesis (RCM) reaction is a very efficient method for the construction of many functionalized carbocycles and heterocycles from acyclic diene or enyne precursors.

By studying the process of producing ammonium chloride after the double decomposition of the waste residue ---sodium chloride and sulphuric acid, we can see that only under the condition of being given certain temperature, density, andproportion, ammonium chloride can be made after adding alkali, washing, absorption of active carbon, and crocking.

Study on the effect of salt on double decomposition reaction of brine and ammonium bicarbonate was investigated.

Study of the genetic conditions of the metathetical reaction;

The preparation method of potassium pentaborate (KB5O8) was studied with the replacement reaction between potassium chloride and sodium pentaborate solution.