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In light of building chiral gamma - tertiary and quaternary carbon centers of butenolides , three synthetic strategies are included : 1 ) the reactions with furanone derivatives as nucleophiles , 2 ) olefination of gamma , gamma - disubstituted butenolides and 3 ) the reactions by using gamma , gamma - disubstituted butenolides as nucleophiles .
 Chemical: gamma - tertiary and quaternary carbon; Chemical: butenolides; Chemical: gamma , gamma - disubstituted butenolides; Chemical: gamma , gamma - disubstituted butenolides
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Chemical 
Text: {0} 
Answer:
 Chemical: gamma - tertiary and quaternary carbon; Chemical: butenolides; Chemical: gamma , gamma - disubstituted butenolides; Chemical: gamma , gamma - disubstituted butenolides