Preparation and conversion of chiral O-isopropylidene-protected 4-aminocyclohexenol to various key intermediates toward narcissus alkaloids
摘要:
Enantiomerically pure 4-amino-5,6-O-isopropylidenedioxycyclohex-2-en-1-ol, conveniently prepared by the union of O-isopropylidenedioxycyclohexadiene with camphor-based chloronitroso ester, was employed in the synthesis of versatile key intermediates toward narcissus alkaloids. (C) 2002 Elsevier Science Ltd. All rights reserved.
Switch in asymmetric induction sense in cycloadditions using camphor-based nitroso dienophiles
摘要:
We have observed a unique reversal in the absolute stereochemistry of the principal adducts from the cycloadditions of camphor-based acylnitroso dienophiles as compared to the adducts obtained through reactions of the corresponding camphor-based chloronitroso compounds. (C) 2002 Elsevier Science Ltd. All rights reserved.