The present invention is directed to the synthesis of 2-chloro-cis-[5a(S)-9a(S)-(5a,6,7,8,9,9a-hexahydro)]dibenzofuran-4-carboxy lic acid by a stereospecific catalytic heteroannulation synthesis free of undesirable 8-chloro-2,6-methano-2H-3,4,5,6-tetrahydro-1-benzoxocin-10-carboxylic.
本发明涉及通过立体特异性催化杂环合成自由的8-
氯-2,6-甲基-2H-3,4,5,6-四氢-1-苯并噁啉-10-
羧酸的不良反应,合成2-
氯-顺式-[5a(S)-9a(S)-(5a,6,7,8,9,9a-六氢)]
二苯并呋喃-4-羧酸。