Oracle Upgrade path as Per Metalink Note 2189854.1  ...

Database Server Upgrade/Downgrade Compatibility Matrix (Doc ID 551141.1)

Direct Upgrade to 12.2:

Source Database	Target Database
11.2.0.3 and higher	12.2.0.x
12.1.0.x (12.1.0.1 - 12.1.0.2)	12.2.0.x

Indirect Upgrade to 12.2:

Source Database	Upgrade Path	Target Database
7.3.3 (lower)	7.3.4 --> 9.2.0.8 --> 11.2.0.3 or higher	12.2.0.x
8.0.5 ( or lower )	8.0.6 --> 9.2.0.8 --> 11.2.0.3 or higher	12.2.0.x
8.1.7 ( or lower )	8.1.7 --> 9.2.0.8 --> 11.2.0.3 or higher	12.2.0.x
9.0.1.3 ( or lower )	9.0.1.3 --> 9.2.0.8 --> 11.2.0.3 or higher	12.2.0.x
9.2.0.7 ( or lower )	9.2.0.7 --> 11.2.0.3 or higher	12.2.0.x
10.2.0.4 ( or lower )	10.2.0.4 --> 11.2.0.3 or higher	12.2.0.x
11.1.0.6	11.1.0.6 --> 11.2.0.3 or higher	12.2.0.x
11.2.0.1	11.2.0.1 --> 11.2.0.3 or higher	12.2.0.x

Helpful metalink note ..

Note: 2173141.1 Complete Checklist for Manual Upgrades to non-CDB Oracle Database 12.2

Note: 2173144.1 Complete Checklist for Manual Upgrade for Multitenant Architecture Oracle Databases from 12.1. to 12.2.

Note: 2189854.1 Complete Checklist for Upgrading to Oracle Database 12.2 using DBUA for Known Issues and Alerts

Note: 2239820.1 12.2.0.1 Base Release – Availability and Known Issues