Question

When the cyclopentene derivative shown below is treated with OsO4, compound A is formed as essentially the exclusive product with only a tiny trace of B being formed. What is the most reasonable explanation for this? H3C CH3 Нас- H3C H3C H3C HaC 3 он OsO4 OH CH3 CH3 CH3 он A, 99% B, <1% O B is not formed to any extent because it would place the methyl group and tert-butyl group both axial O The tert-butyl group effectively shields one face of the pi-system from attack by Os04. Only A can adopt the proper chair conformation O Having all the carbon groups cis- as in A, is the most stable arrangement for any molecule O The methyl group repels the tert-butyl group in the transition state for forming B.

Answer 1

Ans: B (The tert-butyl group effectively shields one face of the pi-system from attack by OsO4.).