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[2 + 2]‐Cycloadditions to Strained Bridgehead Olefins. II. Diphenylketene
Author(s) -
Becker Konrad B.,
Hohermuth Martin K.,
Rihs Grety
Publication year - 1982
Publication title -
helvetica chimica acta
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.74
H-Index - 82
eISSN - 1522-2675
pISSN - 0018-019X
DOI - 10.1002/hlca.19820650122
Subject(s) - chemistry , bicyclic molecule , ene reaction , enantiomer , cyclobutanone , stereochemistry , crystal structure , medicinal chemistry , crystallography , organic chemistry , ring (chemistry)
Abstract The strained bridgehead olefins bicyclo [3.3.1]non‐1‐ene ( 1 ), bicyclo [4.2.1 ]non‐1(8)‐ene ( 2 ), and bicyclo [4.2.1]non‐1‐ene (3), and the comparable monocyclic ( E )‐1‐methylcyclooctene ( 4 ) react with diphenylketene ( 6 ) to give a single cycloadduct 7 , 8 , 9 and 10 , respectively, in which the diphenyl‐substituted C‐atom is bound to the bridgehead. The structure of the cyclobutanone 8 has been determined by X‐ray analysis of a twin crystal obtained by crystallization with spontaneous enrichment of enantiomers.