に先立って => before; prior to ~ N2
に[先立「さきだ」]って/に[先立「さきだ」]ち/に[先立「さきだ」]つ => Before A occurs/takes place N2
Time, Situation
を契機に => as a good opportunity/chance to N2
Expected
を[機「き」]に => Use A as an opportunity N1
Time, Situation
を[契機「けいき」] => As a good opportunity A, (do) B N2
Information, Report
をきっかけに/を契機に => with… as a start; as a result of; taking advantage of N2