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Most Requested Journal Articles 4Q06-Chemistry and Related
Following is one of the journal articles most requested by researchers using CAS electronic products.
CAPLUS COPYRIGHT 2007 ACS on STN
Asym. synthesis of structurally unique marine natural product antheliolide A (I) is described. Key steps include (1) partial acetal exchange of di-Me acetal II (R = Me, Y = (CH3)2CHCH2CH2) into mixed acetal II (R = CH2CO2Me, Y = (CH3)2CHCH2CH2, III) by heating with Me glycolate in the presence of pyridinium tosylate; (2) diastereoselective [2+2] cycloaddn. of a triethylammonium salt derived from the corresponding acid of ester III, leading to IV (Y = (CH3)2CHCH2CH2) in which stereocenters were correctly established at each carbon of the four-membered ring; (3) chain extension of IV into sulfone V (Y = (CH3)2CHCH2CH2), and conversion of V into nine-membered ring VI (Y = (CH3)2CHCH2CH2) via treatment of V with MeOCOCl and DBU-mediated cyclization; (4) mild oxidative cleavage of the lactone ring in VII (Y = (CH3)2CHCH2CH2) into aldehyde VIII (Y = (CH3)2CHCH2CH2) and transformation into I. The synthesis of I has also resulted in the clarification of its abs. configuration, which had not been detd. previously. Updated 7/31/2007 8:41:10 AM
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